Orca Population Genetics by Kate Ashdown

kashdown1 — 2024-06-25 00:24:19 UTC

I wonder what orcas think of us?

2024-06-25 00:30:43 UTC

There are two classifications of Orcas the 'transients' and the 'residents'. The two classifications are defined by the Orcas behaviour and geographical location.

2024-06-25 00:33:12 UTC

Orcas from different geographical regions were examined, DNA being extracted using standard phenol–chloroform methods. (A method that separates nucleic acids from other cellular substances)

2024-06-25 00:34:04 UTC

Larger mammals tend to show low genetic diversity due to their small effective population size and historical bottleneck events.

2024-06-25 00:34:05 UTC

There are two populations of Orcas off the Pacific Northwest Coast however there is a difference in culture. One population is aggressive and hunts and kills large mammals, whilst the others are more docile and eat salmon. The different Orcas populations don't interact with one another, meaning there is no evidence of gene flow between the residents and the transients

2024-06-25 00:35:52 UTC

A study found that the same mtDNA haplotypes were present in different oceans and different hemispheres.

2024-06-25 00:42:52 UTC

Orca populations stemmed from a small founding group and spread out inhabiting different niches worldwide. As they inhabited new areas with differing selection pressures they adapted their behaviours this created a bottleneck event where orcas would breed with other orcas that had traits desirable to their culture. Now each culture is genetically diverse enough to call each a different species and different cultures of orca will not breed with other cultures