Basic SNP / RSID question

Question

[eddy.vasile]

23andme provides 610545 RSID records (SNP, Chromosome, Position, Genotype). I compared mine to a person who is not related to me in any way and about 42% of the genotypes match. Wondering which genotypes for which RSID record must match in order to show relation,

Thank you.

EDIT

Let me rephrase the question:

How many identical SNP of half genotypes do I have to match before I can assume genetic relation?

Also, does it matter which chromosome and what position on the chromosome?

Any ideas, links, references etc. would be great.

Thanks

[eddy.vasile]

Found this:

http://www.isogg.org/wiki/Identical_by_descent

Good enough for now.

Answer 1

[Kamil]

If you're comfortable with scientific literature and want to see equations to deal with SNP data, I might recommend having a look here:

http://www.nature.com/nrg/journal/v16/n1/full/nrg3821.html#snp-based-measures-of-relatedness

To get a better sense of how genetic relatedness is computed and what it means, I might also recommend looking at information provided by 23andme:

http://blog.23andme.com/news/announcements/how-many-relatives-do-you-have/

[eddy.vasile]

Thanks. Read it. Interesting but too general. I need precise counts of SNPs and such. Found enough material at ISOGG

http://www.isogg.org/wiki/Identical_by_descent

Answer 2

[eddy.vasile]

Okay, I found this:

http://www.isogg.org/wiki/Identical_by_descent

Good enough for now.