Haplogroups

We mentioned earlier in this chapter that haplotypes are a set of results of markers for a particular individual. When several similar haplotypes are categorized together, they compose a haplogroup. Haplogroups are useful for deep ancestry research (that is, research that is further back than the advent of surnames) and for placing a geographical context around the possible origin of the individuals within the haplogroup.

Y chromosome haplogroups are categorized by the letters A through R by the Y Chromosome Consortium (YCC). (The Y Chromosome Consortium is a group that studies and publishes findings about the Y chromosome. You can find out more about it at ycc.biosci.arizona.edu/.) These letter designations are based on mutations of certain locations of the Y chromosome. For instance, if an individual has a mutation at the M89 loci, they fall into a haplogroup between F and J. If the individual has a mutation at both the M89 and M170 loci, they are classified in the I haplogroup.

When you submit a sample to a DNA testing company, the results you receive usually include your haplogroup. You can then take that haplogroup and go to the National Geographic Genographic Project page to learn more about the origins of the haplogroup — here's how:

1. Point your Web browser to the National Geographic project site at www3.nationalgeographic.com/genographic/index.html.

At the top of the blue portion of the page are links to the different sections of the site including Main Menu, Genetics Overview, Atlas of the Human Journey, and Your Genetic Journey.

2. Click on the Atlas of the Human Journey link.

This page contains a timeline followed by an introductory paragraph about the Atlas. Beneath the introduction in the black area are two buttons — Genetic Markers and Journey Highlights.

3. Select Genetic Markers.

In the right column is a listing of haplogroups for both mitochondrial and Y chromosome. Scroll down to the Y chromosome area.

4. Click on the Y chromosome haplogroup that interests you.

We are interested in Haplogroup I. So, we click on the link titled Y chromosome Haplogroup I.

Figure 10-5 shows a map of the migration path of Haplogroup I and some text describing attributes of the haplogroup. The haplogroup migrated from the Middle East into the Balkans and later into central Europe.

Haplogroups can also be used to show the genetic distribution of individuals in a particular geographic area. For example, Doug McDonald maintains a map of the distribution of haplogroups at www.scs.uiuc.edu/~mcdonald/ WorldHaplogroupsMaps.pdf. So, if you are interested in finding out the distribution of Haplogroup I in Europe, you can match the color (pink) on the pie charts to determine how prevalent the haplogroup is in a particular area. From this chart, you can see that Haplogroup I has a strong concentration in Scandinavia and northwest Europe. Another Y chromosome haplogroup map is located on the DNA Heritage site at www.dnaheritage.com/ ysnptree.asp. This map is interactive and allows you to filter the map to show only the haplogroup that interests you. Figure 10-6 shows the map. At the top of the map are letters representing the haplogroups. To filter the hap-logroups, move your mouse pointer over one of the letters. The map will only show the distribution for that haplogroup.

As haplogroups are large collections of haplotypes, it is useful to break down haplogroups into subgroups that have common traits. These subgroups are referred to as subclades. Subclades can help genealogists get a clearer picture of the geographical setting of that portion of the haplogroup.

Although the typical Y chromosome test can suggest a haplogroup, it normally takes additional testing to confirm the haplogroup and a subclade to that haplogroup. In these additional tests, particular positions of the Y chromosome are examined for differences called single nucleotide polymorphisms (SNP) or "snips." Some SNPs are very common and apply to a large population of people within a haplogroup. Other SNPs can be unique to an individual or a family — referred to as private SNPs. New SNPs are constantly being discovered and that sometimes results in changes to the labels of subclades or the discovery of new subclades. To find the most up-to-date list of subclades, take a look at the International Society of Genetic Genealogy (ISOGG) Y-DNA Haplogroup Tree at www.isogg.org/tree/Main06.html.

Figure 10-5:

Explanation of Y chromosome Haplogroup I at the National Geographic Genogra-phic Project site.

Figure 10-5:

Explanation of Y chromosome Haplogroup I at the National Geographic Genogra-phic Project site.

Figure 10-6:

Interactive haplogroup distribution map at DNA Heritage filtered for Haplogroup I.

Figure 10-6:

Interactive haplogroup distribution map at DNA Heritage filtered for Haplogroup I.

Dna Haplogroup

To illustrate how subclades work, look at our Haplogroup I example. As you can see from the haplogroup distribution map in Figure 10-5, Haplogroup I has a concentration in Northern Europe and a concentration in the Balkans. If you are in that haplogroup, you might be curious about which region your direct male ancestor came from. To find this out, SNP tests would be conducted on several areas of the Y chromosome including those called M253, M307, P30, P40, S31, and P37.2. If a mutation is found at loci M253, M307, P30, P40, the subclade is I1a — a subclade found in southern Norway, southwestern Sweden, and Denmark. If mutations are found at S31 and P37.2, the subclade is I1b1* — found in the western Balkans. Figure 10-7 shows the subclades of Haplogroup I.

After you discover the haplogroup of your results, you can then join a Y chromosome project for particular haplogroup. Through a haplogroup project, you might be able to find out more about the origins of the haplogroup or the subclade within the haplogroup and communicate with others who are studying the same genetic group. To find a project for your haplogroup, see if your DNA testing company already has a project for it, or do a search using a general Internet search engine such as Google for something like "Y-DNA Haplogroup I project."

Figure 10-7:

The subclades of Haplogroup I from the ISOGG Web site.

Q tñ I u hitp tfwWW isogtj Or^rrm/lSOGG.H;iji(|rpl litrnl

II si M227 (Ewnitdy I1*i)

-TTjI iftmj

gjjl "

ñu» M1.2 (WJM.IKfcnonirllb!) ÍIÍ.11. M ': (formaty

TlLlt! Mlfil iftyrmnlyTll^J |III; SU, S}0.532.SW (»ddeii IllbJ7!

Ubis M223, N24 (TvriBíHylie a]íí> shfwrj a; 12)

[ 1 t.i j 11 Mi'M (forflurf? lie t. rJf : ihown li'ii .Ml "V

► Sms et al (2001) found U250 f> be equivalent t-> M223, but was n«t tested against M2W, 379, P'/S or P9I>. in addition, U150 is n«t identical t' S30, S32, S33. or 524 nor has it been tested agaavrt these SNPi.

Was this article helpful?

0 0

Post a comment