Genetic Testing

Over the course of the last decade, the definitions of health and disease have been transformed by advances in genetics. Genetic testing has enabled researchers and clinicians to detect inherited traits, diagnose heritable conditions, determine and quantify the likelihood that a heritable disease will develop, and identify genetic susceptibility to familial disorders. Many of the strides made in genetic diagnostics are direct results of the Human Genome Project, an international thirteen-year effort begun in 1990 by the U.S. Department of Energy and the National Institutes of Health, which mapped and sequenced the human genome in its entirety. The increasing availability of genetic testing has been one of the most immediate applications of this groundbreaking research.

A genetic test is an analysis of human deoxyribonucleic acid (DNA), ribonucleic acid (RNA), chromosomes, and proteins to detect heritable disease-related genotypes, mutations, phenotypes, or karyotypes (standard pictures of the chromosomes in a cell) for the purposes of diagnosis, treatment, and another clinical decision making. Most genetic testing is performed by drawing a blood sample and extracting DNA from white blood cells. Genetic tests may detect mutations at the chromosomal level, such as additional, absent, or rearranged chromosomal material, or even subtle abnormalities such as a substitution in one of the bases that make up the DNA. There is a broad range of techniques that can be used for genetic testing. Genetic tests have diverse purposes, including screening for and diagnosis of genetic disease in newborns, children, and adults; the identification of future health risks; the prediction of drug responses; and the assessment of risks to future children.

There is a difference between genetic tests performed to screen for disease and testing conducted to establish a diagnosis. Diagnostic tests are intended to definitively determine whether a patient has a particular problem. They are generally complex tests and commonly require sophisticated analysis and interpretation. They may be expensive and are generally performed only on people believed to be at risk, such as patients who already have symptoms of a specific disease.

In contrast, screening is performed on healthy, asymptomatic (showing no symptoms of disease) people and often to the entire relevant population. A good screening test is relatively inexpensive, easy to use and interpret, and helps identify which individuals in the population are at higher risk of developing a specific disease. By definition, screening tests identify people who need further testing or those who should take special preventive measures or precautions. For example, people who are found to be especially susceptible to genetic conditions with specific environmental triggers are advised to avoid the environmental factors linked to developing the disease.

READ MORE From this below

www.encyclopedia.com/topic/Genetic_Testing.aspx#1

www.encyclopedia.com/topic/Genetic_Testing.aspx#4

What are the types of genetic tests?

ghr.nlm.nih.gov/handbook/testing/uses

Genetic Testing: What You Should Know?

familydoctor.org/familydoctor/en/prevention-wellness/staying-healthy/healthy-living/genetic-testing-what-you-should-know.html

(Go to the bottom of this website below, many many links to this subject very interesting reading)

Explore This Subject

www.nature.com/scitable/topicpage/ethics-of-genetic-testing-medical-insurance-and-651

What does genetic testing involve?

Genetic testing usually involves having a sample of your blood or tissue taken. The sample will contain cells containing your DNA and can be tested to find out whether you are carrying a particular mutation and are at risk of developing a particular genetic condition.

In some cases, genetic testing can be carried out to see if a foetus is likely to be born with a certain genetic condition by testing samples of amniotic fluid (the fluid that surrounds the foetus in the womb) or chorionic villi cells (cells that develop into the placenta) extracted from the mother’s womb using a needle.

Depending on the condition(s) being tested for, the blood or cell samples will then be tested and examined in a genetics laboratory to check for a specific gene, a certain mutation on a specific gene or any mutation on a specific gene.

www.nhs.uk/Conditions/Genetics/Pages/genetic-testing-and-counselling.aspx

How genetic conditions are inherited

Each cell in the body contains 23 pairs of chromosomes. One chromosome from each pair is inherited from your mother and one is inherited from your father.

The chromosomes contain the genes you inherit from your parents. There may be different forms of the same gene – called alleles.

For example, for the gene that determines eye colour, you may inherit a brown allele from your mother and a blue allele from your father. In this instance, you will end up with brown eyes because brown is the dominant allele. The different forms of genes are caused by mutations (changes) in the DNA code.

The same is true for medical conditions. There may be a faulty version of a gene that results in a medical condition, and a normal version that may not cause health problems.

www.nhs.uk/Conditions/Genetics/Pages/Facts.aspx

Welcome to UKGTN

The UK Genetic Testing Network is an advisory organisation that provides commissioning support to the NHS and DH for NHS patients in the  UK CLICK ON THIS LINK   www.ukgtn.nhs.uk/

 

A service of the U.S. National Library of Medicine

Genetic Disorders A to Z

and related genes and chromosomes Find a specific condition or related topic by the first letter: CLICK HERE  www.ghr.nlm.nih.gov/BrowseConditions

Genes click here: www.ghr.nlm.nih.gov/BrowseGenes

Chromosomes Information about specific chromosomes: CLICK HERE  www.ghr.nlm.nih.gov/chromosomes

Concepts & Tools

for understanding human genetics: Handbook Help Me Understand Genetics: CLICK HERE:  www.ghr.nlm.nih.gov/handbook

*LOOK HERE*

Genetics Home Reference 

More than 1,100 health conditions, diseases, and syndromes

obtains definitions from several sources: CLICK HERE:  https://ghr.nlm.nih.gov/

Resources and Patient Support

 Each of the following categories provides links to relevant genetics resources on the web. CLICK HERE:  www.ghr.nlm.nih.gov/Resources

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Genomics England is delivering the 100,000 Genomes Project.

We are creating a new genomic medicine service with the NHS – to support better diagnosis and better treatments for patients. We are also enabling medical research.

http://www.genomicsengland.co.uk/

The 100,000 Genomes Project

The project will sequence 100,000 genomes from around 70,000 people. Participants are NHS patients with a rare disease, plus their families, and patients with cancer.

http://www.genomicsengland.co.uk/the-100000-genomes-project/

What does SWAN / being undiagnosed mean?

SWAN stands for Syndrome Without A Name.

It is a term used to describe disabled children who are thought to have a genetic syndrome or condition that doctors have so far been unable to identify.  Many of these children have had lots of tests including blood tests, microarray, lumber punctures, EEG’s, ECG’s and MRI’s but they have all come back negative.

http://undiagnosed.org.uk/information-and-resources/what-does-swan-being-undiagnosed-mean

What is the DDD study?

Map of the UK showing locations of the NHS Regional Genetics ServicesLocations of the Regional Genetics Services

The Deciphering Developmental Disorders (DDD) study aims to find out if using new genetic technologies can help doctors understand why patients get developmental disorders. To do this we have brought together doctors in the 24 Regional Genetics Services, throughout the UK and Republic of Ireland, with scientists at the Wellcome Trust Sanger Institute, a charitably funded research institute which played a world-leading role in sequencing (reading) the human genome. The DDD study involves experts in clinical, molecular and statistical genetics, as well as ethics and social science. It has a Scientific Advisory Board consisting of scientists, doctors, a lawyer and patient representative, and has received National ethical approval in the UK.

The DDD study is jointly funded by the Health Innovation Challenge Fund – a parallel funding partnership between the Wellcome Trust and the UK Department of Health – and the Wellcome Trust Sanger Institute and is supported by the NHS National Institute for Health Research.

Dr Helen Firth, Consultant Clinical Geneticist at Addenbrooke’s Hospital, Cambridge, says:

“Deciphering Development Disorders offers a win-win to patients, clinicians and scientists alike. It could significantly improve our understanding and management of these rare conditions and provide new avenues of research into treatments for scientists to pursue.”

We have spent four years collecting DNA and clinical information from over 12,000 undiagnosed children and adults in the UK with developmental disorders and their parents. The DDD team is absolutely committed to analysing and re-analysing all the genomic data from families in the study over the coming years to try to find a diagnosis for as many children as possible. Recruitment of new patients into DDD ended on April 3rd, 2015, but the DDD team is working closely with the NHS and Genomics England to ensure that this type of genetic testing is continued for families with developmental disorders in the future.

http://www.ddduk.org/intro.html

Publications

Very interesting

Data sharing is a fundamental part of DDD to aid diagnoses and discoveries in the future. We aim to publish as much of our research as possible in peer-reviewed publications to increase the understanding of developmental disorders. Below is the list of DDD manuscripts published so far. They include papers describing our methods and key findings, as well as manuscripts specialising in individual genes or specific developmental disorders.

http://www.ddduk.org/publications.html

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Complexed

What is neurofibromatosis type 1?

NF1

Neurofibromatosis type 1 is a condition characterised by changes in skin colouring (pigmentation) and the growth of tumours along nerves in the skin, brain, and other parts of the body. The signs and symptoms of this condition vary widely among affected people.

Beginning in early childhood, almost all people with neurofibromatosis type 1 have multiple café-au-lait spots, which are flat patches on the skin that are darker than the surrounding area. These spots increase in size and number as the individual grows older. Freckles in the underarms and groyne typically develop later in childhood.

Most adults with neurofibromatosis type 1 develop neurofibromas, which are noncancerous (benign) tumours that are usually located on or just under the skin. These tumours may also occur in nerves near the spinal cord or along nerves elsewhere in the body. Some people with neurofibromatosis type 1 develop cancerous tumours that grow along nerves. These tumours, which usually develop in adolescence or adulthood, are called malignant peripheral nerve sheath tumours. People with neurofibromatosis type 1 also have an increased risk of developing other cancers, including brain tumours and cancer of blood-forming tissue (leukaemia).

During childhood, benign growths called Lisch nodules often appear in the coloured part of the eye (the iris). Lisch nodules do not interfere with vision. Some affected individuals also develop tumours that grow along the nerve leading from the eye to the brain (the optic nerve). These tumours, which are called optic gliomas, may lead to reduced vision or total vision loss. In some cases, optic gliomas have no effect on vision.

Additional signs and symptoms of neurofibromatosis type 1 include high blood pressure (hypertension), short stature, an unusually large head (macrocephaly), and skeletal abnormalities such as an abnormal curvature of the spine (scoliosis). Although most people with neurofibromatosis type 1 have normal intelligence, learning disabilities and attention deficit hyperactivity disorder (ADHD) occur frequently in affected individuals.

ghr.nlm.nih.gov/condition/neurofibromatosis-type-1

www.ncbi.nlm.nih.gov/books/NBK1109/

learn.genetics.utah.edu/content/disorders/singlegene/nf1/

www.uab.edu/medicine/genetics/medical-genomics-laboratory/testing-service/131-neurofibromatosis-type-1

Frequently Asked Questions About Genetic Testing

www.genome.gov/19516567

Genetic Testing: What You Need to Know

canstock3734228

www.encyclopedia.com/topic/Genetic_Testing.aspx

www.cancer.org/cancer/cancercauses/geneticsandcancer/genetictesting/genetic-testing-what-you-need-to-know-toc

kidshealth.org/parent/system/medical/genetics.html

About Genetics

man 1

genetics.thetech.org/about-genetics

Now I know nothing about this so I phoned a UK Company and asked can you help me help the Parents to understand better.

They gave me the following info, so you the Parents can learn and maybe understand a wee bit better than you once did.

What your find is very interesting, and proves if you ask for help 9 times out of 10 people in the

know are more than willing to help out.

What is DNA? What is a gene? Whatever you want to know about genetics you’ll find it all here, in helpful bite-size chunks.

About yourgenome  www.yourgenome.org/about

Your about to ENTER a world of mind-blowing info made easy, click on tabs on the pages loose yourself in this

your genome is the place for you to find out everything you want to know about DNA, genes and genomes. From the basic biology to the challenging ethical issues, it’s here for you to discover and explore!

your genome is a website that enables you to find out more about genetics and genomics. You’ll be able to find out what a genome is and how we sequence the DNA from an organism. You’ll also be able to explore what genetics can tell us about an individual and a population and why this can sometimes throw up some tricky ethical questions and debates.

The website is produced by the Public Engagement team at the Wellcome Genome Campus near Cambridge in the UK. The campus hosted the UK’s contributions to the Human Genome Project and is home to leading international scientists in the field of genomics from the Wellcome Trust Sanger Institute and EMBL European Bioinformatics Institute. Together we aim to stimulate interest and encourage informed debate about this fast-moving area of biomedical science. We provide accurate information about genomics and have created films, animations and activities to bring this exciting area of science to life.

What is a genome?

A genome is an organism’s complete set of genetic instructions. Each genome contains all of the information needed to build that organism and allow it to grow and develop.                                                    www.yourgenome.org/facts/what-is-a-genome

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How do you identify the genes in a genome?

After the sections of DNA sequence have been assembled into a complete genome sequence we need to identify where the genes and key features are, but how do we do this?                                                  www.yourgenome.org/facts/how-do-you-identify-the-genes-in-a-genome

What is a genome?

A genome is an organism’s complete set of genetic instructions. Each genome contains all of the information needed to build that organism and allow it to grow and develop.                                                  www.yourgenome.org/facts/what-is-a-genome

genome

Timeline: History of genomics

A timeline depicting the key events in the history of genomics and genetic research alongside those in popular culture. From the discovery of DNA, and the election of Roosevelt, right through to whole genome sequencing and Andy Murray winning Wimbledon for the first time.   www.yourgenome.org/facts/timeline-history-of-genomics

What is gene therapy?

Gene therapy is when DNA is introduced into a patient to treat a genetic disease. The new DNA usually contains a functioning gene to correct the effects of a disease-causing mutation.                               www.yourgenome.org/facts/what-is-gene-therapy

What is inheritance?

Inheritance is the process by which genetic information is passed on from parent to child. This is why members of the same family tend to have similar characteristics.                                                           www.yourgenome.org/facts/what-is-inheritance

What is Down’s syndrome?

Down’s syndrome is a genetic disorder caused by the presence of all or part of an extra copy of chromosome 21.  www.yourgenome.org/facts/what-is-downs-syndrome

What is a chromosome disorder?

A chromosome disorder results from a change in the number or structure of chromosomes.  www.yourgenome.org/facts/what-is-a-chromosome-disorder

What is antibiotic resistance?

Antibiotic resistance is when bacteria develop the ability to survive exposure to antibiotics designed to kill them or stop their growth.  www.yourgenome.org/facts/what-is-antibiotic-resistance

What is genetic testing?

Genetic testing is an incredibly useful tool for identifying changes or mutations in DNA that could lead to genetic disease.  www.yourgenome.org/facts/what-is-genetic-testing

What is a genetic disorder?

A genetic disorder is a disease that is caused by a change, or mutation, in an individual’s DNA sequence.  www.yourgenome.org/facts/what-is-a-genetic-disorder

What is a chromosome?

cromosozn

Chromosomes are bundles of tightly coiled DNA located within the nucleus of almost every cell in our body. Humans have 23 pairs of chromosomes.  www.yourgenome.org/facts/what-is-a-chromosome

Zoom in on your genome VIDEO

This animation shows where and how the human genome is stored within our cells. www.yourgenome.org/video/zoom-in-on-your-genome

DNA replication

This 3D animation shows you how DNA is copied in a cell. It shows how both strands of the DNA helix are unzipped and copied to produce two identical DNA molecules.                                                   www.yourgenome.org/video/dna-replication

MRSA VIDEO

This animation shows you how antibiotic resistant strains of bacteria, such as MRSA, can develop and spread, particularly in hospitals. www.yourgenome.org/video/mrsa

Cancer: Rogue Cells  Video

This animation describes how cancer grows within the body and how different factors can lead to cancer development.  www.yourgenome.org/video/cancer-rogue-cells

What is achondroplasia?

achondroplasia-091003130855-phpapp01-thumbnail-4

Achondroplasia is a genetic disorder affecting bone development that results in short-limb dwarfism.  www.yourgenome.org/facts/what-is-achondroplasia

dwaft

Adverse drug reactions

An adverse drug reaction is when a medication is given as instructed and at a normal dose has an unwanted or harmful effect on a patient. www.yourgenome.org/stories/adverse-drug-reactions

Sneeze Zone

Through this fun activity, you can learn more about the spread of microbes and their potential to infect people. www.yourgenome.org/activities/sneeze-zone

Treating the bubble babies: gene therapy in use

Some children with severe combined immunodeficiency (SCID), a genetic disorder characterised by a reduced number of immune cells, have been treated using gene therapy.                                                                                     www.yourgenome.org/stories/treating-the-bubble-babies-gene-therapy-in-use

Researchers at UCLA announced today that they had cured 18 children who were born with the so-called Bubble Baby disease, a genetic disorder that leaves the young sufferers without a working immune system, putting them at risk of death from infections, even the common cold.    abcnews.go.com/Health/ucla-researchers-announce-gene-therapy-cure-18-bubble/story?id=26982064

biotechnology-part-2-60-638

 

Genome Generation

Debate current and potential issues in genetics and genomics with this card-based discussion activity.  www.yourgenome.org/activities/genome-generation

DNA

DNA

 

With thanks for the above info from the UK Company who gave me this info above  www.ebi.ac.uk
PLUS THANK YOU to www.yourgenome.org/

Date: Oct 11, 2015

The largest number of simultaneous gene edits ever accomplished in the genome could help bridge the gap between organ transplant scarcity and the countless patients who need them

October 11, 2015 (BOSTON) — Never before have scientists been able to make scores of simultaneous genetic edits to an organism’s genome. But now in a landmark study by George Church, Ph.D., and his team at the Wyss Institute for Biologically Inspired Engineering at Harvard University and Harvard Medical School, the gene editing system known as “CRISPR–Cas9” has been used to genetically engineer pig DNA in 62 locations – an explosive leap forward in CRISPR’s capability when compared to its previous record maximum of just six simultaneous edits. The 62 edits were executed by the team to inactivate retroviruses found natively in the pig genome that has so far inhibited pig organs from being suitable for transplant in human patients. With the retroviruses safely removed via genetic engineering, however, the road is now open for the possibility that humans could one day receive life–saving organ transplants from pigs….. Credit: Wyss Institute at Harvard University

READ MORE 

http://wyss.harvard.edu/viewpressrelease/222

WATCH VIDEO OF WHAT THESE GUYS ARE DOING FOR US

http://www.youtube.com/user/wyssinstitute

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inheritance2

Chromosomes and Rare Chromosome Disorders in General

Chromosomes

Introduction

Author Beverly Searle BSc(Hons) PhD CBiol MSB

Rare chromosome disorders include extra, missing or rearranged chromosome material but do not include the more common chromosome conditions such as Down’s Syndrome. Using the latest technology, it is now possible for smaller and more complex chromosome defects to be identified. The amount of chromosome material duplicated, missing or re-arranged can vary a great deal. This means that it may be difficult to identify two people who have exactly the same chromosome disorder. The clinical problems of those affected can also vary enormously even when the chromosome diagnoses are similar.

Individually rare chromosome disorders are indeed very rare but collectively they are common. In fact, at least one in every 200 babies is born with a rare chromosome disorder, many babies having symptoms from birth or early childhood. The rest might be affected when they grow up and try to have babies of their own – multiple miscarriages, fertility problems, stillbirths or the birth of a disabled child. Some of these chromosome disorders are so rare that they are actually unique. It is usually immediately following diagnosis that affected families and individuals have the greatest need for emotional and practical support and above all, for information. But even among the more common “rare” disorders, it is likely that the professionals in the local community – the GP, Social Worker or even hospital specialists – will have never before come across anyone with the same disorders.

The usual sources of support are not available to affected families, yet the effects of the disorders can be devastating. The vast majority of families have a desperate feeling of isolation. Under the umbrella of Unique membership, families can benefit from mutual support and linking even though the chromosome disorders may be quite different.

The effects of rare chromosome disorders can be very varied. The vast majority of carriers of balanced rearrangements will have no symptoms but might have problems in reproduction. Where there has been a loss or gain of chromosome material, the symptoms arising might include a combination of physical problems, health problems, learning difficulties and/or challenging behaviour. The combination and severity of effects occurring very much depend upon which parts of which chromosomes are involved. The outcome for the affected children can be quite different. In general, loss of a segment of a chromosome is more serious than the presence of an extra copy of the same segment. Defects of chromosomes 1 to 22 are usually far more serious than those of the sex chromosomes X and Y.

It is very important that a child’s chromosome disorder is specified in as much detail as possible. The description of a person’s chromosome make-up is called their GENOTYPE. Sometimes children with the same genotype will show similar problems. However, even children with the same genotype can differ in some or even nearly all of their problems. Why should this be? The genotype as seen under a light microscope is called a KARYOTYPE and only gives us the “big” picture. New technologies like array CGH analysis and next generation sequencing (NGS) allow us to look at chromosome and DNA changes at a much greater magnification and often show us that the actual breakpoints in the chromosome might be many genes apart. But even that does not explain all the differences. Even brothers and sisters with the same genotype inherited as the result of a parent’s chromosome rearrangement can still develop differently. There are many other factors besides a person’s chromosome disorder that affect how they develop, for example, the unique mixture of genes on their other normal chromosomes, the environment in which they are raised and so forth. Sometimes a particular chromosome disorder will give a similar pattern of problems. If enough children are born with this similar pattern, then this can be called a SYNDROME.

There are also some general characteristics of rare chromosome disorders that occur in the majority of affected people to varying degrees. For instance, most people with any loss or gain of material from chromosomes 1 to 22 will have some degree of learning disability and developmental delay. This is because there are many genes located across all these chromosomes that code for normal development of the brain. Defects in any one of them could have a harmful effect on normal development. You might have been dismayed if the doctors and geneticists that you have consulted about your child’s chromosome disorder are not able to give you a definite idea of how your child will be affected in the long term, especially if the disorder is particularly rare.

You might think that the doctors simply do not want to help or can’t be bothered to find out. Nothing could be further from the truth. The point is that, like any other child, your child is UNIQUE and while there might have been other similar chromosome disorders reported in the medical literature, it does not mean to say that your child will develop in the same way. Like any of us, doctors do not have a crystal ball to look into the future. They might only be able to give you an idea of the possible problems that might arise. You, or your family and friends, might have asked what can be done to “cure” a chromosome disorder in your baby or child.

Nothing can be done about the actual chromosome defect because every single one of the billions of affected cells would have to have the missing chromosome material and all the genes involved added or extra chromosome material is taken away and this is not possible yet with today’s technology. However, symptoms caused by the chromosome disorder can be treated as they arise and the best environment given in order for the child with the chromosome disorder to reach their full potential.

When parents discover that their child has a rare chromosome disorder, they often find themselves confronted with a very steep learning curve. Any information learnt about genetics in biology classes at school may be a distant memory. Here we will try to provide you with the basic facts about chromosomes and the different types of rare chromosome disorders. If you find the information a bit complicated, please don’t be put off but do ask if you aren’t sure what anything means.

For the rest of this click on the link below

http://www.rarechromo.co.uk/html/ChromosomesAndDisorders.asp

protean dna

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ANATOMY OF OUR GENES

The Human Body

science-behind_human-body_575x473

 The human body is made of some 50 trillion to 100 trillion cells, which form the basic units of life and combine to form more complex tissues and organs. Inside each cell, genes make up a blueprint for protein production that determines how the cell will function. Genes also determine physical characteristics or traits. The complete set of some 20,000 to 25,000 genes is called the genome. Only a tiny fraction of the total genome sets the human body apart from those of other animals.

Cells

science-behind_cell

Most cells have a similar basic structure. An outer layer, called the cell membrane, contains a fluid called cytoplasm. Within the cytoplasm are many different specialised “little organs” called organelles. The most important of these is the nucleus, which controls the cell and houses the genetic material in structures called chromosomes. Another type of organelle is mitochondrion. These cellular power plants have their own genome and do not recombine during reproduction.

 Chromosomes

science-behind_chromosomes

Chromosomes carry hereditary, genetic information in long strings of DNA called genes. Humans have 22 numbered pairs of chromosomes and a single pair of sex chromosomes—XX in females and XY in males. Each chromosomal pair includes one inherited from the father and one from the mother. If unwound, the microscopic DNA strands in one cell’s nucleus would stretch to over six feet in length.

DNA

science-behind_dna

DNA (deoxyribonucleic acid) is the set of genetic instructions for creating an organism. DNA molecules are shaped like a spiral staircase called a double helix. Each stair is composed of the DNA bases A, C, T, and G. Some segments of these bases contain sequences, like A-T-C-C-G-A-A-C-T-A-G, which constitute individual genes. Genes determine which proteins individual cells will manufacture, and thus what function particular cells will perform.

GENETIC SIGNPOSTS

Shuffling the Deck

For most of our genome, we receive half of our genes from our father and a half from our mother. Each half represents a shuffled combination of DNA passed down to us from our ancestors. This recombination process makes it difficult to study lines of descent because it creates a genetic mix of everyone who has come before.

Fortunately for anthropological geneticists, there are parts of the genome that are passed down un-shuffled from parent to child. In these segments, the genetic code is varied only through occasional mutations—random spelling mistakes in the long sequence of letters that make up our DNA.

When these mutations are passed down through the generations they become markers of descent.

Y Chromosome

science-behind_y-chromosome-new-labels

The Y chromosome is the sex-determining chromosome in humans. While all other chromosomes are found in matching pairs, it is the mismatch of the Y with its partner, the X chromosome, that determines gender—men have a mismatched pair (Y and X), while women have two X chromosomes. Because the Y does not have an identical matching chromosome, most of it (the non-recombining region, or NRY) escapes the shuffling process known as recombination that occurs every generation in the rest of our genome. This allows the Y to be passed down through a purely male line, changed only by random mutational events.

Mitochondrial DNA (mtDNA)

science-behind_mtdna

 

 

If the Y chromosome traces the male lineage back through history, then the mitochondrial genome (mtDNA) can be considered its female counterpart. Mitochondria are self-reproducing structures found inside the cells of all higher organisms, typically present in hundreds of copies per cell. They are responsible for generating most of the energy used by the cell. Because there are no mitochondria in the head of a mature sperm, they are passed down solely from mother to offspring. One region of particular importance in mtDNA is the hypervariable region (HV 1 and 2), where the rate of mutation has been shown to be up to a hundred times greater than that of the nuclear genome. Because of its much shorter length (several hundred nucleotides versus millions of nucleotides for the Y), the HV region can be quickly scanned to reveal many informative mutational events that have been passed down through the maternal line.

PLEASE CLICK ON THE LINK BELOW TO READ MORE
We Would like to say THANK YOU to National Geographic for this. We stumbled across this in our research, Please go to their site watch the, Breaking the Code, VIDEO and a lot more.

https://genographic.nationalgeographic.com/science-behind/genetics-overview/

https://genographic.nationalgeographic.com/science-behind/

Now this is very interesting, worth watching if nothing else  https://genographic.nationalgeographic.com/

mtDNA and Mitochondrial Diseases

Did you know that you have a second genome? Small cellular organelles called mitochondria contain their own circular DNA. What happens to your cells when this DNA mutates?

Click on the RED areas below to be taken elsewhere for more info.

Did you know that your cells contain several thousand copies of an organelle that maintains its own genome? And that instead of being linear, like the chromosomes found in the nucleus, the genome of this organelle is circular? This organelle is the mitochondrion, the powerhouse of eukaryotic cells. In contrast to the human nuclear genome, which consists of 3.3 billion base pairs of DNA, the human mitochondrial genome is built of a mere 16,569 base pairs. Despite its small size, the mitochondrial genome can be used to establish maternal family ties, thanks to its maternal pattern of inheritance. Mutations in the mitochondrial genome have also been associated with diverse forms of human disease and ageing.

Mitochondrial Anatomy and Physiology

This schematic diagram depicts a mitochondrion and some of the biological pathways that take place in this organelle. The outer mitochondrial membrane is an oval, and the inner mitochondrial membrane has many folds called cristae.

(Figure 1)

 Mitochondria are spherical, double-membrane-bound organelles that rely on the distinct functions of their two membranes: the outer mitochondrial membrane and the inner mitochondrial membrane (Figure 1). The outer mitochondrial membrane contains porins that allow the passage of molecules smaller than 5 kilodaltons; it also contains a large multiprotein translocase complex that recognises mitochondrial signal sequences on larger proteins and permits their passage. The inner mitochondrial membrane contains all of the components of the electron transport system and the ATP synthase complex; it also has many invaginations, called cristae, that greatly increase its total surface area. The double membranes form two mitochondrial compartments: the intermembrane space, located between the inner and outer mitochondrial membranes, and the matrix, located inside the inner membrane. Mitochondrial DNA is housed in the mitochondrial matrix.

New Breakthrough in Stem Cell Therapy for Mitochondrial Diseases

http://mitochondrialdiseasenews.com/2015/07/17/new-breakthrough-stem-cell-therapy-mitochondrial-diseases/

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Trisomy 8 Mosaicism Syndrome

What Is Trisomy 8 Mosaicism?

T8mS is a rare disorder, affecting males more often than females

Trisomy 8 mosaicism syndrome (T8mS) is a condition that affects human chromosomes. Specifically, people with T8mS have three complete copies (rather than the typical two) of chromosome 8 in their cells. The extra chromosome 8 appears in some of the cells, but not all. The symptoms of this syndrome vary considerably, ranging from undetectable to, in some cases, severe.

An extra chromosome in all cells is a condition called full or complete trisomy 8, which is deadly and can cause miscarriage during the first trimester of pregnancy. Trisomy 8 mosaicism is caused by a problem between the sperm and egg in which some cells don’t divide properly. The condition is a chance occurrence and is not hereditary.

http://www.healthline.com/health/trisomy-8-mosaicism-syndrome#Overview1

Mosaic Trisomy 8 Syndrome

Trisomy 8 mosaicism is a rare genetic syndrome which affects one in every 25,000 to 50,000 live borns. The male-to-female ratio is close to 5:1. In live births trisomy, 8 is almost always associated with mosaicism. The characteristic findings of mosaic trisomy 8 are high stature, facial dysmorphic features, short and wide neck, long thin trunk, narrow shoulder and pelvis, skeletal abnormalities such as camptodactyly, arthrogryposis, vertebral malformations, absent or hypoplastic patellae and deep palmar and plantar furrows. Additional features include agenesis of the corpus callosum, corneal opacity and strabismus, cardiac and urinary abnormalities. Most patients present a moderate intellectual deficit, with some patients having a normal intelligence. There is a great phenotypical variability and there is no correlation between the percentage of trisomy cells and phenotypic variability.

A 4-year-old female patient was hospitalised because of dysmorphic facial features and multiple congenital anomalies. She was born to healthy, non-consanguineous parents at term with a birth weight of 3500 g by spontaneous vaginal delivery. At 28 weeks of gestation, the ventricular dilation was diagnosed on USG. On physical examination, her weight was 14400 g (75 centiles) and height was 98 cm (50 centiles). She had deep-set eyes, epicanthus, blue sclerae, broad upturned nose and nostrils, long philtrum, low-set ears, high arched palate and everted lower lips, long thin trunk, clinodactyly, narrow shoulder and pelvis, halluces valgi, deep palmar and plantar furrows (Fig. 1). Laboratory investigations revealed normal hemogram, liver and kidney function tests and urinalysis. Ophthalmologic examination revealed strabismus and bilateral corneal clouding. She had a delayed bone age of 36 months at 48 months. She had thoracolumbar scoliosis between Tl 1/12 on radiological imaging. Chest examination and echocardiography were normal. Ultrasonographic examination of the abdomen revealed ectopic right kidney with a rotation anomaly. Cranial MRI showed partial agenesis of the corpus callosum. Ankara Developmental Screening Inventory (ADSI), prepared for Turkish children revealed less than 20% results for language, and adaptive personal and social skills. ADSI also revealed normal results for the fine motor but 30% less for gross motor. The cytogenetic analysis revealed a mosaic karyotype: 47,XX,+8[3]/46,XX[17]. The parents did not accept performing a cytogenetic diagnosis based on fibroblasts.

https://www.questia.com/library/journal/1P3-2657224031/mosaic-trisomy-8-syndrome-with-a-novel-finding-of

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