Y-DNA testing involves looking at segments of DNA on the Y chromosome (found only in males). The segments which are examined are referred to as genetic markers and occur in what is considered "junk" DNA.
STR markers
A chromosome contains sequences of repeating nucleotides known as short tandem repeats (STRs). The number of repetitions varies from one person to another and a particular number of repetitions is known as an allele of the marker. An STR on the Y chromosome is designated by a DYS number (DNA Y-chromosome Segment number). The example below shows the allele of Rumpelstiltskin's DYS393 marker is 12. That means that sequence of nucleotides repeats 12 times.
SNP markers
An SNP is a change to a single nucleotide in a DNA sequence. The relative mutation rate for an SNP is extremely low. This makes them ideal for marking the history of the human genetic tree. SNPs are named with a letter code and a number. The letter indicates the lab or research team that discovered the SNP. The number indicates the order in which it was discovered. For example M173 is the 173rd SNP documented by the group who uses the letter M.
STR markers
A chromosome contains sequences of repeating nucleotides known as short tandem repeats (STRs). The number of repetitions varies from one person to another and a particular number of repetitions is known as an allele of the marker. An STR on the Y chromosome is designated by a DYS number (DNA Y-chromosome Segment number). The example below shows the allele of Rumpelstiltskin's DYS393 marker is 12. That means that sequence of nucleotides repeats 12 times.
SNP markers
An SNP is a change to a single nucleotide in a DNA sequence. The relative mutation rate for an SNP is extremely low. This makes them ideal for marking the history of the human genetic tree. SNPs are named with a letter code and a number. The letter indicates the lab or research team that discovered the SNP. The number indicates the order in which it was discovered. For example M173 is the 173rd SNP documented by the group who uses the letter M.
No comments:
Post a Comment