Title of Patent: DNA forensic test to differentiate between close paternal relatives
Status: PCT Filing (Published as: WO2015097479 A1)
Licensing status: Ready for exploitation
Priority filing date: 24-Dec-2013
UCLan research is developing Rapidly Mutating (RM) YSTRs can differentiate between closely related males. A 13 locus multiplex PCR kit RM-YPlex 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.
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.
Many Y-STRs are unable to distinguish between related males sharing the same paternal lineage. Since mutations in these Y-STRs are relative 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 a 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 rapidly mutating Y chromosome short tandem repeats (RM Y-STRs) in a sample of interest.
RM YSTRs are genetic loci that are amplified through Polymerase Chain Reaction (PCR). Multiple loci can be investigated in a single reaction but it means that the primers have to be constructed appropriately and the reaction has to be optimised to a high level. Our research has achieved that and is 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. Rapidly Mutating (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 simpler, easier and quicker. This was not possible before we developed this tool.
We started working on the concept in early 2012 and we had the working prototype i.e. all markers amplifying simultaneously in later 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 from different samples amplification as Electropherogram plots.
The present invention relates to methods and kits for use in determining the alleles of rapidly Mutating short tandem repeats located on the Y chromosome. The current literature describes rapidly mutating STRs, amplified through 3 multiplex reactions. Our vision was to be able to amplify all the 13 RM Y STRs simultaneously.
The work makes possible kits for use in determining the alleles of rapidly Mutating short tandem repeats 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.
Forensic Science providers around the world can use this product for determining the identity. Paternity determination companies can use it in complex kinship cases. Life Technologies and Promega have marketed a number of multiplex STR and Y STR kits. Recently Promega marketed a kit Y-23 that includes 2 RM Y STRs and 21 other genetic markers. Life Technologies is about to market a kit called Y-Plus where they have added 5 RM Y-STRs and other markers Thus there is a potential for commercialisation of this product as an additional multiplex kit.
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