My connections to the Iberian Peninsula as well as my wife’s connections to the Middle East have given me further incentive to delve further into the practical realities of genealogical DNA testing. First of all, This kind of type of discussion can get technical actually fast. What we are talking about here is usually haplogroups. Here is usually the definition of a haplogroup coming from the Wikipedia article, Haplogroup.
A haplotype is usually a group of genes in an organism which are inherited together coming from 1 parent, as well as a haplogroup (haploid coming from the Greek: ἁπλούς, haploûs, “onefold, simple” as well as English: group) is usually a group of similar haplotypes which share a common ancestor with 1-nucleotide polymorphism mutation.
I am going to leave in all the cross references to allow you to do your own study of This kind of issue. Quoting coming from the article further:
In human genetics, the haplogroups most commonly studied are Y-chromosome (Y-DNA) haplogroups as well as mitochondrial DNA (mtDNA) haplogroups, both of which can be used to define genetic populations. Y-DNA is usually passed solely along the patrilineal line, coming from father to son, while mtDNA is usually passed down the matrilineal line, coming from mother to offspring of both sexes. Neither recombines, therefore Y-DNA as well as mtDNA change only by chance mutation at each generation with no intermixture between parents’ genetic material.
In genealogical DNA testing, we encounter another type of test; the autosomal DNA test. Here is usually as simple an explanation of autosomal DNA as you can find coming from Wikipedia: Genealogical DNA test.
Autosomal DNA is usually the 22 pairs of chromosomes which do not contribute to sex. These are inherited exactly equally coming from both parents as well as roughly equally coming from grandparents to about 3x great-grandparents. Inheritance is usually more random as well as unequal coming from more distant ancestors. Generally, a genealogical DNA test might test about 700,000 SNPs (single-nucleotide polymorphisms). Like mtDNA as well as Y-DNA SNPs, autosomal SNPs are alterations at 1 point inside genetic code. Autosomal DNA recombines each generation. Therefore, the number of markers shared which has a specific ancestor decreases by about half each generation. [I edited some typographical errors, although I am leaving in all the links]
Essentially, the Y-DNA as well as mtDNA tests can go back thousands of years, although the autosomal DNA test results become quickly attenuated with time. coming from a genealogical standpoint, the main issue is usually the “margin of error” with all three types of tests. If we look at the “AncestryDNA Terms as well as Conditions (United States)” we find the following statements:
We attempt to ensure which all Content on the Website is usually complete as well as accurate. Despite our efforts, the Content may occasionally be inaccurate or incomplete as well as we make no representation which the Content on the Website is usually complete, accurate, reliable or error-free.
The Terms as well as Conditions go on to explain:
We make no express warranties or representations as to the quality as well as accuracy of the Content, the Website or the Service, as well as we disclaim any implied warranties or representations, including although not limited to implied warranties of merchantability, fitness for a particular purpose, or non-infringement, to the full extent permissible under applicable law. We offer the Content, the Website as well as the Service on an “as is usually” basis as well as do not accept responsibility for any use of or reliance on the Website, Content or Service, or for any disruptions to or delay inside Service. In addition, we do not make any representations as to the accuracy, comprehensiveness, completeness, quality, currency, error-free nature, compatibility, security or fitness for purpose of the Website, Content or Service.
Of course, This kind of does not address the accuracy of the AncestryDNA test at all. the idea simply states which they are not going to tell you how accurate the tests actually are.
So how accurate are the DNA tests? Dick Eastman had a post not long ago which addressed This kind of issue. He linked to an interesting news story on Yahoo TV entitled, “Investigation Puts Ancestry DNA Kits to the Test Among Sets of Triplets.” The newscasters threw in a set of quads for not bad measure. The real issue with all of the tests is usually the margin of error.
The term “margin of error” is usually defined as follows coming from Wikipedia: Margin of error:
The margin of error is usually a statistic expressing the amount of random sampling error in a survey’s results. the idea asserts a likelihood (not a certainty) which the result coming from a sample is usually close to the number one could get if the whole population had been queried. The likelihood of a result being “within the margin of error” is usually itself a probability, commonly 95%, though various other values are sometimes used. The larger the margin of error, the less confidence one should have which the poll’s reported results are close to the true figures; which is usually, the figures for the whole population. Margin of error applies whenever a population is usually incompletely sampled.
Margin of error is usually often used in non-survey contexts to indicate observational error in reporting measured quantities.
For the DNA tests results to have a greater degree of believability, they should include a clear statement of the probable margin of error since the test results are certainly incompletely sampled. There could be quite a few explanations why the identical triplets came up with different percentages reported for a DNA test, although the real issue is usually, again, the margin of error. This kind of is usually especially true when the reported relationships are based on very tiny percentages of shared DNA.
DNA testing still features a long way to go before the idea is usually entirely useful beyond a few generations.
There is usually always more to say about DNA