Частоты мутаций Y-STR локусов в 2008 году

+ STR rate ranges as of 2008 for 16 Y STRs STRsite Mutation rate (x 10−3) LB 96%CI 'rate' UB 96%CI Notes DYS19 1.5 2.4 3.5 23 of 9658DYS385 1.4 2.1 3.0 31 of 14896DYS389I 0.95 1.8 3.0 14 of 7862DYS389II 1.8 2.8 4.2 22 of 7849DYS390 1.4 2.3 3.5 21 of 9140DYS391 2.0 3.04.5 28 of 9089DYS392 0.18 0.55 1.3 5 of 9053DYS393 0.36 0.89 1.8 7 of 7842DYS437 0.60 1.5 3.1 7 of 4672DYS438 0.051 0.43 1.5 2 of 4709DYS439 3.8 5.7 8.4 27 of 4686DYS448 0.19 1.6 5.7 2 of 1258DYS456 1.8 4.8 10 6 of 1258DYS458 2.8 6.4 12 8 of 1258DYS635 1.6 3.8 7.4 8 of 2131GATA H4.1 0.71 2.2 5.1 5 of 2294 From table 1. Sanchez Diz et al. 2008. Note some of the N in the 17 STR are quite low in frequency
A Y STR is a short tandem repeat (STR) on the Y chromosome. Y STRs are often used in forensics, paternity, and genealogical DNA testing. Y STRs are taken specifically from the male Y chromosome. These Y STRs provide a weaker analysis than autosomal STRs because the Y chromosome is only found in males, which are only passed down by the father, making the Y chromosome in any paternal line practically identical. This causes a significantly smaller amount of distinction between Y STR samples. Autosomal STRs provide a much stronger analytical power because of the random matching that occurs between pairs of chromosomes during the zygote making process.

Y STRs are assigned names by the HUGO gene nomenclature committee (HGNC). Some testing companies have different formats for the way STR markers are written. For example, the marker DYS455 may be written as DYS455, DYS 455, DYS#455, or DYS# 455. The scientific standard accepted by HUGO and NIST is DYS455.

There are regions on DNA that are made up of multiple copies of short repeating sequences of bases (for example TATT) which repeat a variable number of times depending on the individual. These regions, called "variable number short tandem repeats", are what is looked at when performing STR analysis. The likelihood of two people having the same number of repeated sequences is extremely small, and becomes even smaller the more regions that are analyzed. This makes up the basis of short tandem repeat analysis.

In the United States, 13 different autosomal STR loci are used as a basis of analysis for forensic purposes. If crime scene DNA is ample and all 13 autosomal loci accessible, the likelihood of two unrelated people matching the same sample is around one in one billion. The application of a confidence interval accounts for database size and sampling variation. The Y haplotype frequency (p) is calculated using the p = x/N formula, where x is equal to the number of times the haplotype is observed in a database containing N number of haplotypes. For example, if a haplotype has been observed twice in a database of N = 2000, the frequency of that haplotype will be: 2/2000 = 0.001. Reporting a Y haplotype frequency, without a confidence interval, is acceptable but only provides a factual statement regarding observations of a Y haplotype in the database. An upper confidence limit for the probability of the Y haplotype in the population should be calculated using the method described by Clopper and Pearson (1934). This uses the binomial distribution for the probabilities of counts, including zero or other small numbers that are found for Y haplotypes.