How many Y-STRs are there?

It is envisioned that if in a criminal case, a Y haplotype match is established with any of the commercial Y-STR kits, the full set of 13 RM Y-STRs shall be analysed to test whether the matching suspect, or his close or distant paternal male relatives, has left the trace at the crime scene.

What are Y-STR values?

A Y-STR is a short tandem repeat (STR) on the Y chromosome. Y-STRs are usually designated by DYS numbers. The standard Y-chromosome (Y-DNA) test used for genealogical purposes looks at differing numbers of Y-STRs, collloquially known as markers. The combination of Y-STRs tested is known as a haplotype.

What makes Y-STRs useful in forensic sciences?

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. Autosomal STRs provide a much stronger analytical power because of the random matching that occurs between pairs of chromosomes during the zygote making process.

How does Y-STR testing work?

Y-STR testing explicitly targets STR regions on the male Y chromosome that is passed down through the paternal lineage (i.e., father to son). By specifically targeting the Y-chromosome, a Y-STR profile can be unmasked in the presence of female DNA.

What is Y-STR profiling?

Y-STR analysis focuses on short tandem repeats (STRs) found on the Y chromosome, only carried by male individuals. Y-STR analysis is also a valuable tool to trace familial relationships among males, to help identify missing persons, and to assess paternal relationships when the alleged father is not available.

How do you test for Y chromosome?

Y-DNA, mtDNA, and Autosomal DNA Tests

1. Y-DNA tests. Because Y-chromosomes are passed from father to son virtually unchanged, males can trace their patrilineal (male-line) ancestry by testing their Y-chromosome.
2. mtDNA tests.
3. Autosomal DNA tests.

What is STR analysis used for?

STR analysis is a tool in forensic analysis that evaluates specific STR regions found on nuclear DNA. The variable (polymorphic) nature of the STR regions that are analyzed for forensic testing intensifies the discrimination between one DNA profile and another.

How are STRs used to identify individuals?

Because unrelated people almost certainly have different numbers of repeat units, STRs can be used to discriminate between unrelated individuals. These STR loci (locations on a chromosome) are targeted with sequence-specific primers and amplified using PCR. Thus STR analysis provides an excellent identification tool.

How are STR loci named?

The STR locus is named as, for example, D3S1266, where D represents DNA, 3 means chromosome 3 on which the STR locus locates, S stands for STR, and 1266 is the unique identifier. On the basis of different repeat units, STRs can be classified into different types.

What is Y-STR testing?

What does Y chromosome detected mean?

1: Y chromosome DNA is detected: the pregnancy is likely to be male. 2: No Y chromosome DNA detected: the pregnancy is likely to be female. Fetal sex will be confirmed at your 20 week anomaly scan. 3: Test Failure: e.g. insufficient DNA. In a few cases the lab may not be able to demonstrate the presence of fetal DNA.