Equivalent SNP's, Bowman YDNA Project:
With the Big Y-700 DNA test, a male is tested for 111 Y-DNA (STR) markers, plus over 700 more STR markers. He is also tested for thousands of SNP’s. SNP testing determines a male’s confirmed Y-DNA Haplogroup and his place in the Family Tree DNA (FTDNA) Y-DNA Haplotree (sometimes referred to as the giant Y tree for all mankind).

SNP: single-nucleotide polymorphism

SNP’s (pronounced snips) are first known as (private) variants found on the Y-DNA Chromosome. A variant is a mutation and is identified by a group of numbers - based on their place on the Y-DNA Chromosome where the variant occurred. A variant remains private until two males tests positive for the same variant.

Once a variant is shared by two males, the variant becomes a SNP and receives a SNP name. A new branch will then be added to the FTDNA Y-DNA Haplotree The SNP name always starts with a letter and is based on which DNA company finds and identifies the SNP. For example, SNP’s starting with BY or FT were named by Family Tree DNA based on Big Y test results. SNP’s starting with A, were named by the YSEQ DNA company, which is ran by Astrid Krahn and her husband, Thomas Krahn.

SNP’s (variants) have been occurring in a male’s lineages since the beginning of time (the birth of DNA-Adam). Some DNA experts say that SNP’s occur on average about every 4 generations or every 83 years. Some of us refer to SNP’s as our ancestors because they occurred with the births of our ancestors. A male inherits all of the SNP’s which have occurred in his lineage since the beginning (the birth of DNA-Adam).

With genealogical research, you always start with yourself and go back (or upstream). With SNP testing and the Y-DNA Haplotree, it starts with the DNA-Adam and then comes all the way downstream to the person tested.

To view the Family Tree DNA Y-DNA Haplotree, go to the main page of the Family Tree DNA website at: https://www.familytreedna.com/
Then scroll all the way down to the bottom of the page and click on Y-DNA Haplotree under Community. Then enter the Y-DNA Haplogroup where it notes: Go to branch name. For example, type in R-BY33887 and hit enter. You will then be able to view the Y-DNA Haplotree.

SNP blocks: Quite often, a SNP in the Family Tree DNA Haplotree is actually a block of different SNP’s. For example, the SNP R-BY33887 is a block of fifteen different SNP’s including R-BY33887. The other fourteen SNP’s in the R-BY33887 block are called equivalent SNP’s. It is impossible to define the chronological order (time of occurrence) of the SNPs in one block. R-BY33887 will continue to be a block of SNP’s until someone tests positive for part of the SNP’s in the block and tests negative for the others. When this occurs, the block will then be split into two different SNP blocks and a new branch is added to the Haplotree.