FAQ
What are Y-DNA?
This can only be found in the DNA of males. Thus, products offered by FTDNA for the study and comparison of Y-chromosomes are extensive. We usually recommend that members start with a Y-DNA 37 marker test. This is the minimum test to establish a link to one of the many historical "Surname-Adams" of genetically clustered families. Female project members need to find a male relation of the same surname and have them tested to really get the benefit of being in this project.
How does traditional genealogy help the project?
Adding conventional genealogy research to the project investment helps you benefit from your substantial investment in genetic genealogy. Our project supports group members' genealogical research with Y-DNA-related findings. DNA tests inform you of your genetic family; they do not eliminate the need for traditional genealogy research. Minimally, adding your Most Distant Known Ancestor (MDKA) to your account profile will help admins analyze your genetic family sub-group. A best practice is to provide your project admins with your patrilineal lineage, which can help everyone in your genetic family sub-group with their research.
How do Y-DNA matches help the project?
Using an individual's surname, Y chromosome DNA results, and the surnames of genetic matches, it has been possible to pinpoint a ‘Genetic Homeland' for those close genetically matched individuals. Your admins can guide you based on the surnames you match with.
What is a Genealogical Timeframe?
According to FamilySearch.org, a Genealogical Timeframe is "an indefinite time period in which records of identifiable ancestors became available. It is accepted to include from the 1st to the 15th generation or since the adoption of surnames."
What are signature STRs?
Signature STRs are STRs shared by a group of test-takers which can provide a distinctive identification for a specific lineage.
What about privacy?
Maurice Gleeson has an excellent blog post about the benefits of sharing non-sensitive information and what to do if you want your data to remain private.
What is the difference between an STR and an SNP?
This post from Stack Exchange simplifies the descriptions of SNPs and STRs.
SNP: single nucleotide polymorphism
The name tells us that it is a change that affects one single nucleotide and that there can be multiple of these (polymorphism could be rewritten as multiple forms)
From the SNP Wikipedia page:
> A SNP is a DNA sequence variation occurring when a single nucleotide — A, T, C or G — in the genome (or other shared sequence) differs between members of a biological species or paired chromosomes in a human.
So, for instance, if you take eight individuals and sequence their gene XYZ, you may find, at a specific locus (position) on the gene:
Individual 1: AAGGTG **C** AGCAGTC
Individual 2: AAGGTG **T** AGCAGTC
Individual 3: AAGGTG **T** AGCAGTC
Individual 4: AAGGTG **T** AGCAGTC
Individual 5: AAGGTG **C** AGCAGTC
Individual 6: AAGGTG **C** AGCAGTC
Individual 7: AAGGTG **T** AGCAGTC
Individual 8: AAGGTG **T** AGCAGTC
The position highlighted in bold is a SNP. In this case, we only have either C or T (which produces two different alleles for gene XYZ).
This page from University of Utah has a very clear animation on SNPs.
STR: short tandem repeat
These are short, repeated sequences. They're in tandem, that is, one after the other.
STR consists of a few (2-6) nucleotides repeated several (5-100) times.
For instance, this page from the University of Arizona gives the example of D7S280, one STR with sequence (GATA)n (that is, GATA repeated n times)
1 aatttttgta ttttttttag agacggggtt tcaccatgtt ggtcaggctg actatggagt
61 tattttaagg ttaatatata taaagggtat gatagaacac ttgtcatagt ttagaacgaa
121 ctaacgatag atagatagat agatagatag atagatagat agatagatag atagacagat
181 tgatagtttt tttttatctc actaaatagt ctatagtaaa catttaatta ccaatatttg
241 gtgcaattct gtcaatgagg ataaatgtgg aatcgttata attcttaaga atatatattc
301 cctctgagtt tttgatacct cagattttaa ggcc
In this case, variations between individuals reside in the number of times the sequence is repeated.