The major urinary protein (pictured above) allows animals to identify their close relatives by smell alone. (Source: Wikimedia Commons)
It is well-known that animals such as mice are more likely to cooperate with and aid another animal if they are genetically related. This cooperation increases both organisms’ “fitness” within the population as it ensures that the shared genes are more likely to be passed on to the offspring. For instance, female mice help close relatives reproduce and select close relatives to help look after their offspring (1).
So far, scientists have been unable to pinpoint the exact genetic mechanism through which mice identify close relatives whom they have not encountered before. The prevailing hypothesis is that the scent-based genetic marker major histocompatibility complex (MHC) is involved in kin recognition in mice. Recently, researchers from the University of Liverpool have pinpointed another scent-based genetic marker as part of the kin recognition mechanism: the major urinary protein (MUP) (1).
Other researchers have shown that MUP is “highly polymorphic,” meaning that it has a high degree of genetic variation. This feature allows MUP to function as an effective means of conveying genetic similarity or dissimilarity. Due to this large degree of variation, mice that inherit the same MUP genotype are able to be recognized as kin by other mice who share the same genotype (2).
The kin recognition mechanism in mice is reflected in the rearing of offspring, as female mice cooperate with each other to care for offspring in communal nests. The effectiveness of this system for raising offspring is largely dependent upon the compatibility and familiarity between females in the nest. This explains why it is beneficial for female mice to nest with other females who are closely related (2).
The researchers hope that a better understanding of the social structures in animal populations can help foster cooperation and healthier behavior in captive breeding programs (1).
References:
1. University of Liverpool. (2015, September 24). Researchers uncover genetic basis for kin recognition in mice. ScienceDaily. Retrieved from www.sciencedaily.com/releases/2015/09/150924142705.htm
2. Green, J., & Holmes, A. (2015, September 24). The Genetic Basis of Kin Recognition in a Cooperatively Breeding Mammal. Retrieved September 28, 2015.