DNA Basics: Difference between revisions

All human beings are 99.9% identical in their genetic makeup meaning that at out of the 3 billion genes we all have 99.9% are the same in all humans. The places where it is possible for a variance to occur are called, SNP's which stands for Single-nucleotide polymorphisms. SNP's are the main force behind DNA and what gives it it's genealogical value. When two individuals have enough matching SNP's in a row, this becomes a matching segment. The more matching SNP's there are, the bigger the segment is. If a segment is big enough (bigger than 15cm's), it is safe to assume the two individuals share that segment because they both descend from a common ancestor who passed on that segment of DNA to both testers. The more matching segments there and the bigger they are, the closer two test takers are probably related. By testing a sample of a person's SNP's and then comparing them to everyone else in the database, it is possible to identify a person's genetic relatives. Most major companies will test 500-600k SNP's.