Y-Chromosome DNA Genealogy

Y-Chromosome DNA Genealogy

January 2011

DNA analysis can confirm or disprove pedigrees based on paper records. Particularly useful for verifying paternal lines is Y‑chromosome DNA ("Y-DNA"), which is passed down (almost) unchanged from father to son. Mitochondrial DNA, which is passed down along from mother to daughter, is a separate topic not discussed here.

Why Y-DNA?

Humans have 23 pairs of chromosomes in each cell, for a total of 46. One chromosome in each pair comes from our father, the other from our mother. In 22 of the pairs, the two chromosomes look alike, and have matching sets of genetic information. In males, however, the two chromosomes of the 23rd pair are different: males have an 'X-chromosome' and a 'Y-chromosome', whereas females have two matching X-chromosomes. Having a Y-chromosome is what makes you a male. It's pretty obvious that your Y-chromosome had to come from your father, and he got it from his father, who got it from his father, etc, etc. Because family names (surnames) are inherited the same way, we can use the Y-chromosome to follow the direct male line. In the Merrill project and similar 'surname projects', we're looking at only the DNA on the Y-chromosome.

What can be learned from Y-DNA?

Were it not for randomly occurring mutations, all human males would have the same Y- DNA. Mutations occur only rarely, which allows one to determine ancestry. All males having identical or nearly identical Y-DNA must have had a common male ancestor within the last few thousand years or so. However, males having the same surname may not have similar Y-DNA for two reasons: (1) DNA does not reflect non-paternity events such as name changes, adoptions and illegitimate births (2) surnames did not come into general use until about 500 years ago, long after the common ancestor. Furthermore, even males having a common ancestor within the last few thousand years will have slightly different DNA due to random mutations.

What do all those numbers mean?

Imagine DNA being a long string of letters that spell out the genetic 'code'. The DNA 'alphabet' has only four 'letters' (C, G, A, and T). The test looks at short sections of DNA at specific locations (or 'markers') along the length of the Y-chromosome. These markers are places where a short sequence of letters is repeated, over and over again (almost like stuttering), before moving on. The report you receive from the testing lab has a number associated with each marker, which is the number of repeats you have at that marker. The number of repeats stays fairly constant over many generations, but every so often, the number of repeats at a marker can change. By comparing the number of repeats with someone else, you can get an idea of how closely related you are to that person. But instead of looking at just one marker, the test looks 37 or 43 (depending on where the test was done), because the more differences there are between us, the less likely it is that we're related.

Summary:

Similar Y-DNA proves common ancestry in the paternal line.

Males of the same surname do not necessarily have similar Y-DNA.

Minor Y-DNA variations can confirm or disprove pedigrees based on paper records.

How can I get started?

For a living male, a Y-chromosome DNA test for genealogy purposes can be done for under $200 in less than two weeks. The markers that are tested have no biological or medical significance. Results are confidential. Anonymous Y-DNA results for tens of thousands of males are presently available on line, identified by surname. You can optionally choose to make your results (your DNA results, your identity and your pedigree) public. Internet discussion groups, organized by surname, permit related persons to share results and confirm their pedigrees.

Interpretation

There are about 15 human Y-DNA haplogroups. These are subpopulations having specific genetic mutations that occurred up to 60,000 years ago. Broad prehistoric migrations have been traced by determining the prevalence of individual haplogroups is specific geographic regions. Within each haplogroup, teams of researchers are studying when and where more recent mutations occurred. The most recent mutations, occurring during the last 500 years or so, can be associated with particular family surnames by using traditional genealogical methods.

Markers Measured, and prices:
Some labs offer temporary price reductions. Reduced prices in red were offered on the dates indicated.
* 12/18/10-12/31/10 DNAH augmented donations by 20 percent, equivalent to a reduced price of about $125.

testing lab	Ancestry.com	Ancestry.com	DNA Heritage	Family Tree DNA
markers measured	33	46	43	37
before 5/24/10	$149	$179	$149	$149
5/24/10-6/4/10	$149	$179	$129	$149
6/5/10-6/19/10	$149	$179	$129	$119
6/20/10-6/24/10	$149	$179	$149	$119
6/25/10-11/30/10	$149	$179	$149	$149
12/1/10-12/17/10	$149	$179	$149	$119
12/18/10-12/31/10	$149	$179	$125*	$119
beginning 1/1/11	$149	$179	$149	$149

Conversion of Marker Values

This document describes differences in nomenclature, and rules for converting marker values reported by different labs.

Not all labs follow the convention adopted by the International Society for Forensic Genetics (ISFG). Marker H4 is particularly confusing, due to the non-standard definition used by FTDNA. Examples are given.

External Links

Sample certificates and Nomenclature

DNA Heritage (DNAH)

changes in DNAH Heritage nomenclature, Dec 2009

before 2007:

Sample certificate (for Deane Merrill, 10 Feb 2006)
Values reported by DNAH agreed with Merrill project nomenclature.

DYS441=13; DYS442=11; DYS452=6; DYS463=20;

GATA A10=12; TAGA H4=12.

Deane Merrill's DYS464 result reported as (12,13,13,14).

Revised to (12,13,13,13,14) per discussion 9/8/08 with Alastair Greenshields.

December 2007:
Sample certificate (for Deane Merrill, revised 27 Nov 2008)

Values reported by DNAH were revised to the ISFG standard:

DYS441=13+1=14; DYS442=11+5=16; DYS452=6+19=25; DYS463=20+2=22;

GATA A10=12+2=14: GATA H4.1=12+10=22.

October 2009:

Sample certificate (for Deane Merrill, as of 12 Dec 2009)

Online report (for DNAH Merrill surname group including Deane Merrill, as of 11 Dec 2009)
Values reported by DNAH were revised to the ISOGG standard.

          Deane Merrill's values:
                   DYS441=14; DYS442=16; DYS452=25; DYS463=22;
                   GATA A10=14; GATA H4.1=22-10=12.

DNA Ancestry

Sample Raw Results reports for Deane Merrill
DYS441=14; DYS442=16; DYS452=25; DYS463=22;

GATA A10=14; DYS464=(12,13,13,13,14)

GATA H4.1=22
online report, 5 Sep 2008

GATA H4=12
online report, 30 Sep 2009

On 9/30/09 DNA Ancestry updated the H4 marker and its allele value to comply with a recently released industry-wide recommendation by the International Society of Genetic Genealogy (ISOGG). This change was based on the recommendation of ISOGG and a consensus of genetic genealogists. This did not affect the haplogroup assignment.

Sample Paternal Lineage report (for Deane Merrill, 5 Sep 2008

Relative Genetics

Sample certificate (for F. K. Merrill, 10/19/06) This file is private.
Sample certificate (for D. R. Merrell, 2/23/07) This file is private.

Values reported by Relative Genetics agree with pre-2007 DNAH values.

Family Tree DNA

Ordering the FTDNA Y-DNA37 Test (1/9/11)

Sample certificate for Deane Merrill, (1/23/09)

Sample certificate for David W. Merrell (5/24/04)
Online reports for David W. Merrell, as of 12/12/09:

Panels 1-4 (67 markers)
Kittler and DNA-FP

Additional markers
Online reports as of 1/5/10 for:

                   Deane Merrill
                   David W. Merrell
                   Gary L. Merrill (notice H4 result on last page)

Values reported by FTDNA agree with pre-2007 DNAH values except:

(a) FTDNA reports values for H4 that are one less than pre-2007 DNAH TAGA H4;

(b) FTDNA reports values for 452 and 463 that agree with the 10/09 ISOGG standard;

This is true even for FTDNA's palindromic DYS464x test.

DNA-Fingerprint, Thomas Krahn (acquired by Family Tree DNA)

Ysearch, a free public service of Family Tree DNA

Deane Merrill's results were entered manually. H4 was entered as reported by FTDNA.

DYS441=13; DYS442=11; DYS452=6; DYS463=20;

GATA A10=12; "H4"=11; DYS464=(12,13,13,13,14).

"H4" values in Ysearch, if entered automatically, agree with FTDNA. If entered by hand, one cannot know for sure whether the value in Ysearch agrees with FTDNA, or has been modified to agree with pre-2007 DNAH TAGA H4.

Sorenson Molecular Genealogy Foundation (SMGF)

SMGF reports values according to several different conventions, including:

NIST (ISOGG) = Ancestry.com after 9/30/09.

ISFG = intended to be the ISFG standard? GATA H4.1 is one less than the ISFG standard.

DNA Heritage = DNAH after Oct.2009.

Family Tree DNA = values reported by FTDNA.

Ancestry.com = Ancestry.com before 9/30/09.

Genebase v3.4 = genebase.com as of Dec 2009

DNA Reunion, a database maintained by genebase.com

DNA Reunion uses a hybrid nomenclature not used elsewhere. See conversion.htm.

Whose DNA Should You Trace?, Mary Harrell-Sesniak in RootsWeb Review Archives, July 2010

DNA and Genealogy, Joan Young in RootsWeb Review Archives, December 2009