New DNA washing ashore?
Some years ago it was generally accepted that there were two kinds of lions – African and Indian. More recent genetic studies suggested that the western and central African lions were distinct from those occurring in southern and eastern Africa.
Those genetic studies were largely based on analyses of mitochondrial DNA, and were not generally accepted.
Mitochondrial DNA is inherited along maternal lines – fathers of offspring do not contribute any mitochondrial DNA. This means that by analysing only mitochondrial DNA, we might get a “false” picture of the genetic background of populations, as we do not have any knowledge of the “autosomal” DNA – contained in all our cell’s chromosomes and contributed to equally by both parents.
Look at it this way. Say you have a population of humans living on an island in Scotland. The women in that population have been there for endless generations, while the men might have come from many different genetic backgrounds – Vikings, shipwrecked sailors from Spanish armadas, travelling salesmen, etc. So by looking only at mitochondrial DNA, you would say that that island population genetically resembles all other Scots. But you would be missing a huge part of the history of that population.
Now, a study of autosomal DNA by Laura Bertola and co-workers confirmed that an African lion is not the same African lion across the continent. Laura showed that western and central African lions are indeed distinct via paternal DNA, and she also showed that eastern and southern African lions are also distinct from each other. Of course the Indian lions made up the fourth group.
There is evidence that lions in Ethiopia might represent a fifth genetically unique population, but we await confirmation.
So what does this new data mean? Intelligent conservation requires intelligent thinking. We must do better to conserve not only lions but different types of lions. Meaning that the IUCN, CITES, the US Fish and Wildlife Service, the EU Scientific Review Group and all others who seek to allow commercial utilization of lions based only on numbers must revise their policies to recognize genetic biodiversity among lions and not just place them all in one entity called “lion”.
Picture credit: PrisonersofEternity.co.uk