DNA | Gilliams of Virginia
DNA and Gilliam Research
Updated March 16, 2016


Overview
Gilliam DNA data will be added as it comes available. If you would like for your DNA to be posted please contact me.



Background
The most popular ancestry tests are Y chromosome (Y-DNA) testing and mitochondrial DNA (mtDNA) testing, which test direct-line paternal and maternal ancestry, respectively.

Y chromosome (Y-DNA) testing
A man's patrilineal ancestry, or male-line ancestry, can be traced using the DNA on his Y chromosome (Y-DNA) through Y-STR testing. This is useful because the Y chromosome passes down almost unchanged from father to son, i.e., the non-recombining and sex-determining regions of the Y chromosome do not change. A man's test results are compared to another man's results to determine the time frame in which the two individuals shared a most recent common ancestor or MRCA. If their test results are a perfect, or nearly perfect match, they are related within genealogy's time frame.

STR markers
A Y-chromosome contains sequences of repeating nucleotides known as short tandem repeats (STRs). The number of repetitions varies from one person to another and a particular number of repetitions is known as an allele of the marker. Individual Y-DNA sequences or STRs which have proved useful in genealogical DNA work are called markers, and each has a name.

Haplogroup
Haplogroups are large groups of haplotypes that can be used to define genetic populations and are often geographically oriented.

Mitochondrial DNA (mtDNA) testing
A person's matrilineal or mother-line ancestry can be traced using the DNA in his or her mitochondria, the mtDNA, as follows: This mtDNA is passed down by the mother unchanged, to all children. If a perfect match is found to another person's mtDNA test results, one may find a common ancestor in the other relative's (matrilineal) "information table", similar to the patrilineal or Y-DNA testing case above. However, because mtDNA mutations are very rare, a nearly perfect match is not as helpful as it is for the above patrilineal case. In the matrilineal case, it takes a perfect match to be very helpful.

Autosomal DNA
Autosomal DNA testing purports either to determine the "genetic percentages" of a person's ancestry from particular continents/regions or to identify the countries and "tribes" of origin on an overall basis. Admixture tests arrive at these percentages by examining SNPs, which are locations on the DNA where one nucleotide has "mutated" or "switched" to a different nucleotide. Tests' listing geographical places of origin use alleles—individual and family variations on various chromosomes across the genome analyzed with the aid of population databases. As further detailed below, this latter type of test concentrates on standard identity markers



Ancestor
John Gilliam Goochland County, VA
HAPLO

R1b1a2

393

13

390

24

19

14

391

10

385a

11

385b

15

426

12

388

12

439

11

389 1

13

392

13

389 2

29

458

17

459a

9

459b

10

455

11

454

11

447

24

437

15

448

19

449

30

464a

15

464b

15

464c

16

464d

17

460

11

GATAH4

11

YCA a

19

YCA b

23

456

15

607

15

576

19

570

17

CDY a

36

CDY b

37

442

13

438

12

531


578


395S1a


395S1b


590


537


641


472


406S1


511


425


413a


413b


557


594


436


490


534


450


444


481


520


446