December 30, 2007

Uses of mtDNA and Y-choromosome sequences

Deoxyribonucleic acid, more commonly known as DNA, has been arise again and again in the development of biomedical technology. The DNAs, the plan of man, are unique and specific to each individual, even among identical twins. In a word, DNAs of man are like fingerprints that identify each person, its roots and ancestry and ethnic origin, among others.

One of the main uses of DNA tests is the family name or test common ancestor more recent data. Thanks to DNA tests, people can now determine if people in the same family name of the parents. How is this done?

The male human DNA contains chromosome Y. This may tell us if two or more men in the same family name or surname are parents or not. And if they are, the DNA of the Y chromosome can also identify the MRCA or the most recent common ancestor that binds the two men.

In addition to being able to determine the ethnicity of an individual, his relation to another of the same name and their most recent common ancestor, the Y chromosome markers in the human genome sex Men can also provide information on the individual haplogroup. A haplogroup or haplotype is a group of individuals having the same genetic characteristics, giving the details of an individual for his deep ancestral lineage, whether father or mother.

However, given that only men have Y chromosomes, females may determine the same information with any other DNA test, mtDNA testing. Since mitochondrial DNA or mtDNA is transmitted by the mother of both male and female offspring, women do not need to worry about not knowing their roots, their ethnicity and their ties with people who have the same patronymic. Just as men have their Y chromosomes, women have their mtDNA tests to obtain the same information.

In truth, biomedical technology has come a long way in connecting life, past and present.

December 28, 2007

HGC advises DNA testing must be controlled

Great Britain is perhaps very close to a surge of publicly available genetic tests . Yet there are virtually no controls on independent tests before they are put up for sale, and it is notoriously difficult to regulate the allegations made to them by suppliers test. In poor conditions, many could even do more harm than good.

These are the conclusions of the report "More Genes Direct" of the Human Genetics Commission (HGC), released today (Tuesday).

Sir John Sulston, who chairs the HGC, said: "There is no doubt that many tests provided without recourse to a doctor or health professional could lead people totally useless d alarm or give them false reassurance. We have a thriving industry here and we have an urgent need to adapt the rules."

Commission calls for the approval mechanisms much more difficult, accepted codes of conduct and the end of direct advertising to the public for tests and services with important implications on health. Companies offering the tests should be made to prove that they are based on sound scientific data.

Dr. Christine Patch, an author of the report, said: "The HGC is against an outright ban on genetic tests sold directly to the public, but people should be aware of what they buying. My simple advice to the public is that, with a lot of tests on the market today, you are wasting your money. At this point, science is not strong enough to provide tests of several genes. "

The main recommendations of the Commission are as follows:

* A revision of the European directive which deals with genetic tests to get rid of the gaps which exempt market depth Pre-assessment.
* The cessation of direct advertising to the public for testing with major health implications.
* A new regulatory system for non-medical purposes "life" tests that did not fall within the EU directive.

The Commission intends to hold talks with the test providers, regulators and others in early 2008 to review the current system for the marketing of genetic tests.

December 27, 2007

Y-chromosome genealogy and the search for Adam

Chromosome Y can only be found in men. It has the form and function distinctive because it involves sex-determination during embryonic development (A male contains a human X chromosome and one Y chromosome).

Other than that, Y chromosome DNA contains paternal which is used in determining the father of descent (patrilineality), as it is passed from father to son. This is because most of the Y chromosome passes virtually unchanged from generation to generation.

In search of our ancestors from the parent help us understand our roots in our history and anthropology.

Basically, random mutation causes slight changes in the Y chromosome that allow us to elucidate total generations of the two Y chromosomes, which are derived from a common ancestor is also known as time to the most recent common ancestor (TMRCA).

Based on this concept, it is possible to clarify the relationship between the two men to make sure they are really connected with each other. The cutting edge of DNA testing, several genetic markers are used to estimate how men are closely linked to each other what can be done in a very short time and thus trace the paternal line.

There are five million years ago, our Y chromosome had traveled around the world since humans and our primate cousins were separated evolutionary. Y chromosome, Adam was discovered by comparison test on the men in the world capable of building a family tree of mankind shows that the most recent common ancestor of men lived about 60000 years in Africa.

The significance of the date of our common ancestor Y chromosome is that actually gives us an upper limit where our species began to leave Africa between 60000 and 50000 years. This is known as the "Out of Africa" theory.

Although the name "Adam" is just a metaphor, monitoring the results of the most recent common male ancestor of mankind reflect the origin and spread throughout the world are in biblical range of approximately 10000 to 60000 years.

December 26, 2007

The basics about Mitochondrial DNA inheritance and uses for genealogy

The mitochondrial DNA is a type of genetic test that is used to learn more about the mother's side of the family as mitochondrial DNA (also known as mother-DNA) is transmitted from the mother to her children. In this article we will see how the mitochondrial DNA testing is done, what he is used to the differences and testing of nuclear DNA.

DNA mitochondrial DNA is found in the mitochondria of cells and differs from nuclear DNA. The nuclear DNA is a combination of mother, father and DNA, while mitochondrial DNA is inherited only from the mother. When the egg from the mother and sperm from the father join to form the new baby of the tail of the sperm that contains the father of mitochondrial DNA are left out and the fact that the mother of mitochondrial DNA is transmitted to the child.

Like nuclear DNA testing mitochondrial DNA testing is done by first collecting a DNA sample either through a blood sample or through a cheek swab, the cheek swab is the best method. These samples are then sent to laboratories that are testing mitochondrial DNA, in turn, and they analyze the results.

Mitochondrial DNA testing is used for a number of reasons - the first is to establish a direct link to the mother's family on the side of the family, it can also be used in ' ancestry DNA testing to verify the mother descent or forensic DNA testing.

In the 1980's, Dr. Mary-Claire King has also started using mitochondrial DNA to solve cases where a child's parents are unknown. She used a section on mitochondrial DNA which vary considerably and have provided evidence of the mother or grandmother had. Because mitochondrial DNA is passed directly from mother to child through the generations, maternal uncles and aunts should also contain mitochondrial DNA matching that of a child whose parents disappeared, and so if the maternal grandmother can not be found, it is possible to try matching the child with an aunt or uncle.

In conclusion, mitochondrial DNA testing involves testing of mitochondrial DNA, which is passed from mother to child through the generations, and therefore can be used both to make match a child with his maternal grandmother, aunt or uncle, if the mother is absent, but also can be used DNA testing in the side maternal ancestry.

December 24, 2007

DNA Testing has Changed Everything

Since its discovery 20 years ago, the use of DNA for human identity and the relationship of the test has emerged as a powerful tool in both civil and criminal justice systems. DNA tests can reveal if two or more persons are related, as well as determining the nature of their relationship. Today, it is possible to identify people by a single hair, as well as to obtain information on their gender and ethnic background, and in the next two years, to identify their age.

Before the advent of DNA tests, tests of human identity was largely completed by blood typing. Analysis of DNA is now replaced blood and is the most accurate method currently available for identification.

The possibility that the DNA could be used for human identity and the relationship of the test had been examined from the time DNA has been found that the molecule that makes people unique. However, it was not until the discovery of DNA by Professor Alec Jeffreys (now Sir Alec) at the University of Leicester in 1984 when the first trials of the system are available. Like fingerprints classics, where various loops and whorls are compared between two fingerprints, DNA analysis based on the comparison of the DNA of certain characteristics called DNA markers between two individuals. If modes of DNA between samples are identical, then they are likely to come from the same person. If the profiles are not identical but are great similarities, the samples come most likely related individuals. The degree of similarity between the DNA profile is a reflection of the degree of relationship between people.

Currently, DNA testing is routinely used in both criminal and non-criminal. But there's a big difference between DNA testing for civilians and for criminal cases. For civil cases, DNA testing is mainly used to determine the relationship between individuals, while for criminal cases of a crime task must match the suspect.

No criminal in legal practice, DNA testing is used primarily for immigration and child support. In 2004, more than 7000 DNA tests have been made for these purposes in the UK. Where there are no reliable documentary evidence is not available, DNA testing can help to determine different degrees of relatedness between the individuals involved, as well as ethnic origin.

The first time DNA testing has been used for purposes of identity was in the landmark immigration case Sarbah vs. Home Office (1985). In this case, DNA testing was used to prove the relationship between mother-daughter Christiana Sarbah and his son Andrew. Today, the Home Office accepts DNA testing as proof of kinship virtually indisputable. The results will be generally (but not always) to provide conclusive evidence as to whether the individuals in question are related, as alleged.

UK Child Support Agency makes abundant use of DNA tests to determine who the biological parent of a child is to provide support and maintenance of children. Child support is one of the major areas of non-criminal DNA testing.

The adoption of children is another area where DNA analysis is widely applied. Currently, the UK adoption agencies adopt children in families that reflect their ethnic origin. Sometimes it is difficult to determine the ethics of the child and may contribute to DNA testing. People of different races and ethnic groups have their faces and other common characteristics that are typical of this particular race or group. The same applies to their genetic characteristics. Different racial and ethnic groups have genetic markers specific to these groups. Analysis of these markers, it is possible to indicate the proportion of his ancestors who came from various ethnic groups. However, it is impossible to determine at what stage the ancestors have contributed their DNA and also their number. For example, the results of DNA tests of ethnicity can show that the individual has 20% of specific markers to North Europe, 50% in the Middle East, 10% of the Mediterranean and 20% sub-Saharan Africa. Using this information the family with the greatest race of the child may be chosen.

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December 23, 2007

DNA testing and immigration

In most cases, DNA tests for immigration reasons are parental (paternity or maternity), but in some cases, a large parentage or avuncular test is used to prove an alleged relationship. Verification of paternity through DNA testing may be the key to establishing legal residency and citizenship. DNA Laboratory tests have helped thousands of people do. Providers of immigration DNA testing, also provide government agencies, local embassies and immigration clients with results of DNA test interpretation.

The Immigration and Nationality Act requires that the blood and the legal relations are established. In addition to the documentation, a genetic test may be required by a laboratory for DNA analysis. The laboratory must be accredited by the American Association of Blood Banks for Parentage Testing. About 50 laboratories around the world hold this accreditation. Immigration cases may be simply to determine paternity or maternity. In addition, family relationships may also be determined using DNA, with the participation of grandparents, uncles, aunts, brothers and sisters. In the case of a husband and wife, the petitioner may be required to demonstrate that there is no relationship.

The Immigration Act dealing with a case where a child is bound to only one parent differently. The treatment depends on the child is related to the mother or the father. When the child is revealed to the child's biological father, but not the mother, the Home Office usually seeks an explanation of the family on the following items:

1. If the child has been established and lives with the birth mother or natural father.
2. If the child's mother is also seeking entry or whether it meets the conditions for admission.
3. If the father had exercised solely responsible for the child's education.
4. If the father had a previous marriage or undisclosed is in a polygamous marriage.

When a child is bound only to the mother, the situation is different. It is a very delicate matter and it is generally treated with great sensitivity that the child may be illegitimate, and the father may not be aware. The impact of a disclosure of adultery could be disastrous for women. If the child was raised as a child in the family it is generally accepted. If the results of DNA tests indicate that the child was unrelated to the complainant, there could be grounds for the Home Office to grant the request. If it is proved that the child was put in place as a family member, he or she can be categorized as a de facto admission adopted child. In cases where the child is not a biological child of his parents, but it is related to them, the child may qualify as a dependent of a relative other than a parent.

December 22, 2007

DNA testing to predict and diagnose breast cancer

Genetic testing, which is also known as the test based on DNA is the most powerful technique used to test detection of breast cancer. It involves direct examination of the DNA molecule itself.
By using a molecular diagnostic test for determining whether a breast tumor respond to chemotherapy, the doctor's need to identify more precisely patients who can be adequately treated with hormonal therapy alone and which patients will truly benefit if chemotherapy is added to the treatment. With better individualized treatment, we can spare women the side effects of chemotherapy where it is unnecessary.

Breast cancer, like most other cancers, develops when changes occur in genes in the cells of the breast. In this sense, all breast cancer has a genetic component. But "genetic" is not hereditary. It is estimated that only 5% to 10% of all cases of hereditary breast cancer result from a genetic predisposition to the disease. In other words, more than 90% of all cases of breast cancer result from factors that are not inherited, and, in many cases, are not known.

So far, researchers have discovered two genes linked to breast cancer marked BRCA1 and BRCA2-that everyone inherits two: one from our mother and one from our father. When functioning normally, they are supposed to stop the growth of cancer cells in the breast. When these two genes in a pair are damaged, they don't work properly and cancer can develop. People who inherit a damaged BRCA1 or BRCA2 gene from only one parent are at greater risk of developing breast cancer than people who inherit two normal genes. Studies

can estimate the risk among a large number of people who have inherited a mutation, but not increase the risk for any individual woman. Women with a BRCA mutation have about 33% to 50% risk of developing cancer by age 50, and from 56% to 87% risk of the age of 70. Most research focuses on women with a strong family history of breast cancer or ovarian (several female relatives, on the one hand, which had breast and / or ovarian cancer before the age 40 years, cancer in both breasts, and / or cases of male breast cancer).

By being able to identify these genes through particular markers associated with genetics, doctors will know which individuals are more susceptible to cancer and can therefore follow the correct procedure. The earlier the doctor can diagnose cancer, the most effective treatment will be.
Scientists warn, however, that even if they have discovered a gene associated with breast cancer, there is still no cure available. They managed to identify the gene, but currently there is no way to "fix" the gene.
The recent isolation of the BRCA-1 gene has prompted investigators to identify other genes that may contribute to breast cancer, ovarian cancer and breast, ovarian cancer syndrome.