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Genetic ancestry tests are not always able to determine the origin of someone. Learn more about genetic testing of ancestry

Genetic ancestry tests are not always able to determine the origin of someone. Learn more about genetic testing of ancestry

Do these tests really work?

Genomic tests of ancestry have a number of limitations. Providers of these tests compare the results with different databases from previous tests, so ethnicity estimates may not be consistent from one company to another. Unless the company has a very specific database, it is very difficult to state with any degree of precision that an individual of African origin belongs to a certain tribe (a very frequent promise in the marketing of some ancestral testing providers). <

Another limitation of ancestral tests lies in the fact that most human populations have migrated many times during their life history, mingling with close ethnic groups, and thus estimates of ethnicity based on genetic testing may be different from expectations of a person.

In ethnic groups with a smaller range of genetic variation due to the size and history of the group, many members share several polymorphisms and this may hinder the distinction between people who have a relatively recent common ancestor such as fourth cousins degree, of the group as a whole.

How do these tests work?

There are three types of tests Genetic variations on the Y chromosome, passed exclusively from father to child, can be used to explore ancestry in the direct male line. This test can only be performed on men as women do not have a Y chromosome. However, women interested in this type of genetic test usually recruit a male relative to do so.

Y chromosome testing is the most commonly used to investigate cases of genetic linkage with the same surname, since the pattern of many cultures is to carry the surname of the parent generations outside.

Mitochondrial DNA Test:

This type of test identifies genetic variations in DNA contained in mitochondria. Although most DNA is compacted into chromosomes within the cell nucleus, mitochondria (energy-producing cell structures) also have a small amount of their own DNA (known as mitochondrial DNA), which is passed exclusively by the mother. > So, this type of test can be used for both sexes, because all inherit this DNA from the mother. Mitochondrial DNA testing may be useful for genealogy because it preserves information about the direct female ancestral line, which may be lost in family historical records, since the mother's name is not passed in most cultures. >Genomic Ancestry Test

or Single Nucleotide Polymorphism Test:

These tests evaluate large numbers of genetic variations across a person's genome. It gives an estimate of the percentages of European genes, for example. The results are compared with those of other people also submitted to this test to provide an estimate of a person's ethnic origin. For example, the pattern of SNPs (a determinate portion of the genome that reveals ancestral traits) may indicate that ancestry of an individual is approximately 50% African, 25% European, 20% Asian, and 5% of unknown origin. Genealogists use this type of test because the results of Y chromosome and mitochondrial DNA tests, which represent only individual ancestral lines, do not capture an individual's general ethnic background.

Where to find these tests? The tests of genetic ancestry are offered by various companies and organizations, all over the world. Most companies provide online discussion forums and other services to allow people who have been tested to share and discuss their results with each other, which may allow them to discover previously unknown relationships.

On a large scale, results of genetic ancestry of several people can be used by scientists to explore the history of populations as they emerge, migrate and mingle with other ethnic groups.

As we better understand the complexity of the human genome and genomic possibilities of its use, the genetic tests of ancestry have an evolutionary future still distant but absolutely possible. We will also have to master a much higher percentage of genome knowledge (all we know, for now, is only 3% - and we already do wonders) and we also need to develop larger and more complex genomic analysis algorithms. Is there still much to do and know in the world of genetics? which applies to the genomic analysis of our ancestors.


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