In genealogy, the male lineage is traced unambiguously using the Y chromosome because it is only passed down from the father to son. The male-specific portion of the Y-chromosome (MSY) contain an accumulation of mutations throughout time and all individuals carrying a Y chromosome are related through a single XY ancestor who (likely) lived around 300,000 years ago. There are mainly two principal types of tests, haplogroup test based on Single-Nucleotide Polymorphisms (SNPs) and haplotype test based on Short Tandem Repeats (STRs).

Haplogroup test (SNP):

  • Builds the Y-DNA phylogenetic tree, refer to: Phylogenetic Trees >>
  • The number of mutations separating individuals can be translated into a time to most recent common ancestor (TMRCA)
  • Provides for a terminal haplogroup closer to current date (in widely tested haplogroups this test has a low FAR-value).

Haplotype test (STR):

  • Summing a genetic difference between two sets of Y-STR alleles
  • Mutates faster than SNP’s, but do not account well for back and parallel mutations
  • Does NOT provide for a terminal haplogroup (rather a basic haplogroup with a high FAR-value)

Note: when ordering an haplotype test based on STR’s, e.g. FTDNA Y-DNA37 or Y-DNA111 only a basic haplogroup will be defined. Many testers get dissapointed when their result does not provide them with a haplogroup based on a sequenced SNP test.

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