Washington, Apr 18 : A new study from the University of Liverpool has found that female mice recognize inbred males on the basis of their scent alone.
The team led by led by Jane Hurst has discovered that female mice choose to associate with males producing a greater diversity of major urinary proteins (MUPs), even when all else was held equal.
"We conclude that female mice can identify more outbred males by the higher diversity of urinary proteins they produce," said Michael Thom of the University of Liverpool.
Previous studies by the same team have found that wild mice also rely on MUPs to recognize and avoid mating with their close relatives.
"In addition to the multiple signalling roles already identified for MUPs, these proteins may also act as a signal of inbreeding. More outbred animals produce a greater number of different protein forms, and females may be able to recognize these superior males simply by 'counting' the number of proteins they produce, without waiting to see which might win in a fight," Thom added.
The team believes that results in mice increases the possibility that similar behaviours could be widespread in other species.
Heterozygosity means that animals' two copies of a gene are represented by different variants and the extent of an individual's heterozygosity across the genome provides a measure of their inbreeding.
The researchers carefully bred mice to remove the intrinsic correlation between genome-wide heterozygosity and heterozygosity at two gene clusters that they thought might allow direct assessment of genetic diversity through scent.
They found that female mice preferred to associate with MUP heterozygous to MUP homozygous. However, MHC heterozygosity, did not influence the females' preference for nesting partners.
"We now have evidence that females are sensitive not only to the degree of MUP matching with potential mates, but also to genetic heterozygosity at this region within individual males," the researchers said.
"The central role of MUPs in individual recognition, kin avoidance, and heterozygosity assessment make this an ideal system for addressing the function of genetic signals in social and mate choice in vertebrates," they added.
The study appears online in Current Biology, a Cell Press publication.