The six gill shark is a globally distributed deep water sharks that is found circumglobally. In the Mediterranean Sea it is caught often by bycatch by fishermen. In this study genetic variation of the Sixgill sharks of the Mediterranean were assessed and compared to sharks caught outside of the Mediterranean. The genetic connectivity between all the sharks was determined and it was shocking to find that worldwide there was a genetic heterogeneity. By studying the mitochondrial DNA sequence in a specific area in two specific genes, it was found that of the total world population there were sub populations between the Pacific Ocean and the Atlantic Ocean.
Again like last week’s article the discovery of separate stocks worldwide is vital to designing management plans for the overall conservation of this species. The mtDNA analyzed was from 3731bp to 3914bp, this was chosen because it was the most control of all regions in genes of the sharks. The study brought to light 22 different haplotypes, so in essence twenty two groups of genes that were inherited together from a twenty two different single parents. The examination into this shows that over specific geographical separations such as the mid-Atlantic ridge and most abyssal plains, there is a clear cut in the data that shows some haplotypes staying with specific unique areas.
In conclusion the importance of genetics in this study is that without it the separation and the discovery of multiple stocks of Sixgill sharks has made it so scientists worldwide can manage the stocks even better. The haplotypes were found to be not randomly distributed but clustered according to geographically origin, and actually confined to specific sample locations. Without the exploration into the genetics of the shark and using the mitochondrial DNA what was found would not be known.The amazing part is during this study on top of the discovery of separate geographically specific stocks scientists also found that there was no pelagic life stage, this was found by looking at how the mtDNA shapes in the early life history of the elasmobranch. The theme of the paper is that there is entire species that are genetically diverse and by looking at genes it shows that the populations are subdivided into genetically distinct units separated from each other by unique bottom structure.