2023-11-08 09:46:25
08 November 2023
Confusing criminals using DNA from their pets’ hair… And why not? British researchers from the University of Leicester achieved this using cat hair.
In 2022, France had more than 15 million domestic cats, andEcology Global Network estimates that there are at least nearly 600 million cats on Earth. In the UK, around 26% of households own a cat. It is therefore very likely that a criminal will own or be around one. Therefore, collecting cat hair from a crime scene, or from a place where a suspect may have stayed, is in itself a great idea. However, this approach has hitherto encountered technical difficulties. Indeed, unlike human hair, cat hair comes off without its bulb. Therefore, it was difficult to collect sufficiently informative DNA.
Cat hair, evidence in forensic investigations
In an article published in the journal Forensic Science International : Geneticsthe researchers describe a sensitive method capable of extracting maximum information from a simple cat hair, as explained by Emily Patterson, the lead author of the study and a doctoral student at Leicester: “the hair lost by your cat has no roots or bulbs. Therefore, they contain very little usable DNA. In practice, we can therefore only analyze mitochondrial DNA (present in the mitochondria, these energy plants located inside the cell). This is transmitted from the mother to her offspring and is shared between cats related to the mother. This means that hair DNA cannot identify a cat individually. Maximizing information collection was therefore essential for its use for forensic purposes. »
In order to increase the precision of their DNA test, the researchers therefore developed a new method capable of determining the complete sequence of mitochondrial DNA. This device thus guarantees a level of discrimination up to ten times higher than that of the techniques previously used, which were limited to a too short fragment of this DNA.
Soon the same progress for dog hair?
Dr Jon Wetton, from the university’s Department of Genetics and Genome Biology, who co-led the study, illustrates this advance: “In a recent murder case, we applied the usual technique. However, we were fortunate that the suspect’s cat had a rare mitochondrial variant. Without this feature, most cat lineages might not be distinguished from one another. With our new approach, however, virtually all cats have a type of DNA that can now be described as rare. Therefore, the test will almost certainly always be informative if hairs are found. »
Study co-leader, genetics professor Mark Jobling, adds: “In criminal cases where there is no human DNA available to test, animal hair becomes a valuable source of evidence linking the crime and the criminal, and our method makes it much more powerful. The same approach might also be applied to other species, including dogs. »
While the average feline sheds thousands of hairs each year, a single hair contains enough DNA to link a suspect to a crime scene or victim.
-
Source : Patterson E C, Lall G M, Neumann R, et al. Defining cat mitogenome variation and accounting for numts via multiplex amplification and Nanopore sequencing. Forensic Science International: Genetics 67 (2023) 102944.
-
Written by : Hélène Joubert; Edited by: Emmanuel Ducreuzet
1699449514
#Criminals #confused #cats #hair #news
