DNA Ancestry Testing FAQ for Ireland

DNA Origins®  is a distinctive test stating the percentages of your ancestral makeup specified on markers across your 22 pairs of autosomes (non-sex chromosomes); taking into account contributions from your full range of ancestors. Maternal and paternal lineage tests also offered, only report the maternally inherited mtDNA, or the paternally inherited Y-DNA. These lineage tests provide you with information about your direct maternal and paternal lines, as detailed in the diagram beneath.

Generally race includes both a cultural and biological feature of a person or group of people. Physical attributes between populations are often connected by cultural distinctions; separating these two aspects of race has been demanding. The last few decades there has been progression in several fields of science to quantify the issue by declaring that race is “just a social construct”. This may be correct, this would depend what variation between people one is reflecting, it is a fact that there are biological differences between the populations of the world. An obvious example of a biological difference is skin colour. There is a strong genetic aspect to the level of pigmentation in an individual’s skin and there are many differences across the various populations. Pigmentation is only skin deep and a basic heritable trait in relation of the complicated environments in how we live and how these environments affect our individual and group quality of life is far beyond our ability to apprehend as scientists.

BioGeographical Ancestry (BGA) is the phrase specified to the biological or genetic part of race. BGA is a straightforward and objective explanation of the Ancestral origins of a person, in terms of the major population groups. (e.g., European, East Asian, sub-Saharan African, Indigenous American, etc.). BGA estimates are able to signify the mixed nature of many people and populations living today. In many countries across the globe, there has been extensive integration amongst populations that had initially been detached. In the fields of human genetics and anthropology, this integration is known as admixture. BGA estimates can also be understood as individual admixture proportions, which can be stipulated as a series of percentages that add to 100%. For example, an individual may be found to have: 65% European; 19% East Asian; 16% African ancestry, or they may be found to have 100% European ancestry.

The AncestrybyDNA™ test uses a number of selected panel of Ancestry Informative Markers (AIMs) that have been categorized in a great number of well-defined population samples. These markers are chosen on the basis of displaying significant differences in frequency between population groups and can enable us to detail the origins of a particular person whose ancestry is unidentified. For example, the Duffy Null allele (FY*0) is very familiar (approaching fixation or an allele frequency of 100%) in all sub-Saharan African populations. An individual with this allele is especially likely to have some level of African ancestry. Once the analysis of these AIMs, in a sample of a person’s DNA, the likelihood (or probability) that a person is derived from any of the parental populations and any of the possible mixes of parental populations is calculated. The population (or combination of populations) where the probability is the highest is then taken to be the greatest estimate of the ancestral proportions of that person. Confidence intervals on these point estimates of ancestral proportions are also being taken into account and calculated.

The DNA Origins® test present your ancestral proportions with years of extensive and collaborative research of populations signifying the 4 ancestral groups. This research acknowledged 144 informative markers in our DNA, called Ancestry Informative Markers (AIMs). The results give you a 95% confidence interval, which is an indication of the statistical strength of the analysis. Scientists who developed the test have carried out extensive validation studies with various numbers of markers to produce a test that was inexpensively feasible as well as provides the most concentrated statistical data. In a validation study that used a simulated 100% European population, for example, the test results displayed less than 3.3% of total average contribution from African, Indigenous American, and East Asian ancestry, indicating the level of “statistical noise” that is to be expected from the results.

1. Understanding health variations. Are there genetic contributions to the higher rates of hypertension and diabetes in African Americans or the elevated rates of dementia in European Americans? If not, then what are the cultural or environmental differences that underlie the prevailing differences? Studies of these and other diseases require independent, objective measures of BioGeographical Ancestry (BGA).
2. Estimates of BGA can help reconnect individuals separated by adoption, or some other event, with their ancestral populations.
3. Even if a person is not particularly stimulated to reconnect with ancestors, he or she can unravel the past of their family either to verify family tradition or to investigate forgotten or undiscovered roots.
4. It allows clients to compare their ancestral proportions to others in their family, town, city, or county who have chosen to participate. Because it is based on DNA, and unlike the census, this new tool will provide the most accurate demographics data that is possible. We will call this our “personal demographics” tool.

The medical implication of BGA estimate is insignificant. Some diseases are to be found at different frequencies in populations across the globe, hardly any are limited to one group. The usefulness of BGA estimates, in biomedical research, comes from epidemiological analysis where many individuals are analysed together to list very broad statements about differences in risk. Even though these results can be very significant, they have very little meaning regarding the level of risk for any one person in the population.

The mtDNA and Y-chromosomal lineage tests present a different view of someone’s ancestry. It traces and analyses the direct, unbroken maternal and paternal lines, respectively, reverting back to a common ancestor that lived several thousands of years ago. Although these tests may offer information regarding the origin of some of a person’s ancestors, they are partial in that they do not give information about the impact of non-lineal ancestors; for example, spouses along the direct maternal and paternal lines. BGA analysis relies on sequences throughout your genome, so we can provide more details about a larger number of your ancestors.

The current BGA test that DNA Origins®  offers provides information on the scope of ancestry on the continental level for most continents, European (which includes European, Middle Eastern and South Asian groups such as Indians), and African, but we distinguish ancestries within Asia and the Pacific Rim by adding East Asian, (which includes the Pacific Islanders) as an additional group and Indigenous American. Since there will also be interest in defining the levels of ancestry within continents (such as distinguishing Japanese from Chinese, or Northern European from Middle Eastern), we are in the development stages of expanding our portfolio of services with a new level of Ancestry Informative Markers that will present more insight into where within a particular continent a persons’ ancestors were most originated.

Pedigree studies have revealed that the level of admixture follows identified inheritance patterns, aiding the validity of these low values. As previously stated, the confidence intervals are significant for understanding your results and the scores are the most probable estimates from your DNA. If your confidence interval overlaps zero your value may be within the statistical noise threshold of the test and should be considered a possible result. As the number of markers tested increases the statistical noise should decline as confirmation in the change in confidence interval size involving the 2.0 and 2.5 tests.