Introduction
UCLan research is developing Rapidly Mutating Y Chromosome Short tandem repeats (RM Y-STRs) that can differentiate between closely related males. A 13 locus multiplex RM Y-STR PCR kit was developed to simultaneously amplify them, in a robust and sensitive manner down to 0.0625ng template DNA. The test allows full RM Y-STR profile detection out of male/female mixtures, giving reliable results.
Description
Short tandem repeats (STRs) are commonly used for the analysis of DNA in a range of forensic applications, such as the analysis of DNA found at crime scenes. STRs found on the Y chromosome (Y-STRs) are used in determining the presence of male DNA in samples that may also contain female DNA, such as those obtained in sexual assault cases.
Short tandem repeats (STRs) are commonly used for the analysis of DNA in a range of forensic application, such as the analysis of DNA found at crime scenes. STRs found on the Y chromosome (Y-STRs) are used in determining the presence of male DNA in samples that may also contain female DNA, such as those obtained in sexual assault cases.
Many Y-STRs are unable to distinguish between related males sharing the same paternal lineage. Since mutations in these Y-STRs are relatively rare events, the majority of these will be shared between such male relatives.
Certain Y-STRs have been identified as “rapidly mutating”, which for the present purposes indicates that they have mutation rates in the order of 10-2 whereas all the other Y-STRs have mutation rates in the order of 10-3. The use of these markers for identification allows distinctions to be made between even closely related male subjects.
Our research provides a method of determining the alleles of RM Y-STRs in a sample of interest. RM Y-STRs are genetic loci that are amplified through Polymer Chain Reaction (PCR). Multiple loci can be investigated in a single reaction, but it means that primers have to be constructed appropriately and the reaction has to be optimised to a high level. Our research has achieved that and is the first time such a multiplex reaction has been described for the 13 RM Y-STRs.
Since Y-STRs are inherited from the father these remain unchanged since the mutation rates are low (10-3). Thus close relatives cannot be identified by using normal Y-STRs. RM Y-STRs have a high mutation rate (10-2). These are therefore good for identifying close relatives. A single PCR amplification makes the reaction simple, easier and quicker. This was not possible before we developed this tool.
We started work on the concept in early 2012 and we had the working prototype i.e. all markers amplifying simultaneously in the latter part of 2012. All the amplifications have been successful with different male samples. Female samples do not give rise to any amplification results (which should be the case). The system has also been tested with a number of close male relatives to show its application to identify close male relatives. In 2013 we started work on a different enzyme and that also has been successful. Attached are the results form different samples amplification as Electropherogram plots.
The present invention relates to methods and kits for use in determining the alleles of RM Y-STRs located in the Y chromosome. The current literature describes RM Y-STRS, amplified through 3 multiplex reactions. Our vision was to be able to amplify all the 13 RM Y-STRs simultaneously. Additional work is ongoing with relation to this project, so there is potential for collaboration on further developments on this research
CORE ADVANTAGES
The work makes possible kits for use in determining the alleles of RM Y-STRS located on the Y chromosome, using a single reaction for amplifying all the 13 RM Y-STR loci, which avoids the time, resource and human effort of the previous methods. Additional work is ongoing with relation to this project, so there is potential for collaboration on further developments on this research.
APPLICATION
- Forensic Science providers around the world can use this product for determining identity.
- Paternity determination companies can use this in complex kinship cases.