By Bob Grant
ARTICLE EXTRAS
1 that sponging is a socially learned behavior and likely not the result of genetic inheritance.
"We were the first to consider extensive genetic data to actually exclude genetic explanations for the behavior," says Krützen. He and his team took tissue samples from 185 dolphins in Shark Bay, thirteen of which were known adult spongers. Only one of these spongers was male. The researchers genotyped each individual for 12 bi-parentally inherited microsatellite loci and sequenced a maternally inherited control region of mitochondrial DNA for each dolphin.
They found, by considering the mtDNA profiles, that the spongers shared a recent common female ancestor, making them closely related and all part of the same matriline. The researchers considered ten different scenarios, including sex or mitochondrial chromosome linkage, in which the behavior is mediated by a single gene or several closely linked genes; they discounted all of them ...
