Killer Whale Genetics Raise Inbreeding Questions

Another hereditary investigation of Southern Resident executioner whales found that two male whales fathered the greater part of the calves conceived since 1990 that researchers have tests from, an indication of inbreeding in the little executioner whale populace that frequents Washington's Salish Sea and Puget Sound.

Just around 26 of the 76 imperiled whales in the Southern Resident populace are right now reproducing, as per the examination distributed for the current week in Animal Conservation. The predetermined number of reproducing whales lessens the powerful size of the populace, abandoning it less flexible to change and perhaps trading off the survival of individual creatures, said lead creator Michael Ford, a preservation scientist at NOAA Fisheries Northwest Fisheries Science Center in Seattle.

Creators of the exploration additionally incorporate researchers from the North Gulf Oceanic Society and Center for Whale Research. While the new paper expands on prior hereditary examinations, it likewise brings up new issues about in the case of inbreeding might add to the populace's battles. Southern Resident numbers have tumbled to their least point in 30 years.

The investigation recognized four whales as profoundly innate, including posterity of a father-little girl and mother-child match, yet noticed that each of the four are as yet alive. Numerous extra whales might be ingrained to a lesser degree. Different examinations have evaluated that the greater part of Southern Resident calves kick the bucket previously or soon after birth, and the new investigation proposes that inbreeding could be a contributing component.

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Using Genetics to Define Sub-populations of Killer Whales

Population boundaries are often difficult to define for marine mammals but are critical to conservationists and scientists who study natural populations. In the North Pacific Ocean, there are two distinct groups of killer whale (Orcinus orca), one that only eats other marine mammals, such as sea otter and seals, (“transient”) and another that only eats fish species (“residents”). For decades marine mammal scientists have been doing surveys of these populations to map their geographical range but not much is known about the gene flow between the two populations that exhibit very different eating habits. The National Oceanographic and Atmospheric Administration (NOAA) recently funded a study for genetic testing of these populations to better understand the similarity and relatedness coded in the whales’ DNA.

From 2001 and 2010, 462 skin biopsy samples were taken from both residents and transients from the northern Gulf of Alaska to the Sea of Okhotsk. Scientists used both mitochondrial DNA and nuclear microsatellites to analyze the samples. One would think that in the vast open ocean with no true boundaries that gene flow would be common between killer whale populations. However, this study showed that is not the case in the north Pacific Ocean. Data revealed significant levels of population genetic subdivision within the two predominant ecotypes. The fish eating residents are now classified as a single population that ranges from southeast Alaska through the Aleutian Islands and Bering Sea. The marine mammal eating transients showed two genetically distinct stocks that have a slightly overlapping range that begins in the Bering Sea and spreads down to the Prince William Sound. This study helped further map the geographical range and understand the dynamics of the unique populations of killer whales in the northern North Pacific so that NOAA can better manage their habitat. 

Killer whales are cool 

Different types of Orcinus Orca

Scientists have been debating for years whether Killer whales belong to a single species or several different ones, but new DNA evidence seems to show killer whales should be classified in at least four different species. It has always been believed that Orcas have been part of the same species, Orcinus Orca. After been observed more closely scientist are beginning to classify them differently due to their feeding habits and appearances. This is called an Ecotype. Whales from the different Ecotypes do not bread with one another, speak the same dialect, eat the same food, or have the same eye patch.



Scientists have always looked at the mitochondrial DNA from the whales and classified them as a single species, but researchers have come to believe that some species may have mitochondrial DNA that changes more rapidly or slower than others. Therefore looking at just part of the mitochondrial DNA doesn’t give a full picture of genetic variety of killer whales.

Researchers have mapped the full mitochondrial genomes of 139 killer whales from different locations and concluded that the animals fall into several genetically distinct groups.

This changes a lot. Who would have thought that these whales that are so similar actually are very different? I currently do whale research with orcas. This might bring about many different questions when concluding my findings.