Oct 3 : University of Missouri-St. Louis scientists have analysis the DNA sequences from feather lice of the Galápagos Hawk to study how island populations of these birds of prey might have colonized the Galápagos Islands.

The study, published online in the journal Molecular Ecology, focuses on genes from three parasite species restricted to the Galápagos Hawk.

The scientists sequenced the same genes in the hawk to compare levels of genetic variation across these distantly related species. They traced the family tree of each species across the eight-island range, which were each colonized by the hawks and its parasites.

The researchers found the lice’s mitochondrial DNA was more variable than the host’s. The parasite’s family tree revealed how four of the hawk’s eight populations were related to one another – the stepping-stone manner in which, over time, the hawks colonized first one island, then another and another, carrying their lice as they went.

Noah Whiteman, who conducted this study as part of his dissertation at UMSL, said these relationships were previously obscured due to the hawk’s low genetic variation.

He said the results demonstrated how symbionts of larger and more charismatic species, like hawk lice, could tell scientists a great deal about the history of life.

“The parasites are evolutionary heirlooms that were brought to the islands during the colonization of the hawk, but have continued to evolve along with their hawk hosts,” said Whiteman.

“We had a great deal of trouble understanding how the island populations of the hawk were related to one another because of low genetic variation in the hawk’s DNA. The rapidly evolving lice that live their entire lives on these birds have helped illuminate their host’s evolutionary history,” he said. (ANI)