Y-DNA HAPLOTYPES

So, now that we know all about Y-DNA Haplogroups, how do we address the issue of learning how we are related to other individuals?

The Y-Chromosome has definable segments of DNA with known genetic characteristics. These segments are known as Markers. These markers occur at an identifiable physical location on a chromosome known as a Locus. Each marker is designated by a number (known as DYS#), according to international conventions. An excellent reference for this topic is http://www.dnaheritage.com/tutorial1.asp.

Although there are several types of markers used in DNA studies, the Y-Chromosome test uses one type primarily for genealogical or family history. The marker used is called a Short Tandem Repeat (STR). STRs are short sequences of DNA that are repeated numerous times. The variation of the number of repeats of each marker enables discrimination between individuals.

Reading the Test Results

The table below is a shortened version of an actual table used to show our DNA test results. It shows 12 of the 25 markers that most of the participants had tested.

Marker 1   2  3   4    5    6   7   8   9   10  11    12

DYS# 393 390 19 391 385a 385b 426 388 439 389i 392 389ii
      13  26 14  11   12   14  12  12  11  13   13    29

The numbers (1-12) across the top of the table are the marker numbers. They have no significance other than as an easy way to refer to the marker. Note: FamilyTree DNA refers to these numbers as Locus. The second set of numbers across the top of the matrix are DYS# (the actual marker names). The rest of the numbers are the Allele (the number repeats) for a participant at the specified marker. A set of these values is referred to as a Y-DNA Haplotype.

To learn how these numbers are related to the Y-DNA Haplogroups, scientists have performed the STR test on the same individuals who had the SNP test described in the previous email on Y-DNA Haplogroups. The scientists observed that they could use the STR test results to "guess" or to "estimate" a Haplogroup. So when FamilyTreeDNA tests your sample and arrives at a set of 12 or 25 markers, they can use these markers to estimate the Haplogroup.

For example, now that my Haplogroup has been determined by the more expensive, more time-consuming, SNP testing, they can use my STR results to predict that anyone who shares my STR results most likely will also have the same Haplogroup.

So, in our Ivey-Ivie-Ivy DNA Surname Project, my results are Kit #7362. Those who have the same STR results as me (such as Kit #s 8160, 8355, 7724, and 8367) have the same or very similar Haplotype. They are estimated to have the same Haplogroup, and thus probably don't need to pay the extra money for the Haplogroup determination.

So, our Haplotypes are the same or very similar. How related are we? This leads us to the next topic "Tutorial on Most Recent Common Ancestor".