In general, larger species burn energy at a slower rate per unit of mass than smaller species. This is described by Kleiber's Law, which predicts basal metabolic rate as a function of body mass. I understand that there are some physical theories as to why Kleiber's Law should be true, but that's not my question.

My question relates to the fact that closely related species can vary greatly in body size (e.g., lemurs can range in body mass from 30g to 9kg). This being the case, do we have any idea which genes control differences in basal metabolic rates between mammalian species? And are they somehow related to genes that determine the body size of a species?