A new study by N Srinivasan’s lab in the Molecular Biophysics Unit has probed the proteomes – the entire set of functional proteins – of a group of mammals collectively referred to as Afrotheria. Afrotheria includes animals currently living in or originally from Africa, ranging from small insectivorous shrews and golden moles to elephants. The authors found that a large number of ribosomal proteins and olfactory receptors – linked to stress regulation and a heightened sense of smell respectively – were hallmarks of Afrotherian proteomes.  

The authors also report that although Afrotherian proteomes are almost 99% similar, comparisons on a finer scale reveal that elephants have branched out extensively from their Afrotherian relatives. The number of copies of individual proteins and their combinations may have contributed to differences between them.

In addition, their study highlights that elephants have an unusually high number of sperm-protecting proteins. This may be because for animals like the elephant with low reproductive rates and fewer offspring, it is critical to produce high quality eggs and sperm. The presence of more copies of these proteins may boost sperm protection and the success rate of reproduction.