As relatives share genes that are identical by descent, organisms can gain additional fitness benefits by improving the reproductive success of known kin. There are a number of costs associated with close inbreeding, including an increased likelihood of the expression of recessive deleterious alleles and reduced survivorship. The ability to recognise kin therefore enables individuals to improve their inclusive fitness and avoid problems associated with close inbreeding. Female house mice (Mus musculus domesticus) will nest and nurse offspring communally. Choosing an appropriate nest partner is therefore important and competition between nesting females can result in reproductive inhibition and infanticide. Kin selection theory suggests that females could gain inclusive fitness benefits from nesting with relatives. This thesis explores the mechanisms of kin recognition in female house mice in the contexts of social partner choice and inbreeding avoidance. Female house mice recognised unfamiliar relatives, suggesting a phenotype matching mechanism for kin recognition. Females were presented with maternal and paternal half-siblings to investigate recognition template formation. Females nested with maternal but not paternal half-sisters, suggesting that female house mice may use a recognition template learnt from their mother for social partner choice decisions. However females avoided both maternal and paternal half-brothers suggesting that females may use a match-to-self mechanism for inbreeding avoidance. Female house mice were able to identify relatives from urine, suggesting that genetic markers are present in urine. To investigate the molecular markers of kin recognition mice were bred to control for the major histocompatibility complex (MHC) and major urinary proteins (MUPs). Females nested with females that matched for MHC or MUP type, suggesting that both gene families may be used for kin recognition between females. A non-significant trend was observed for females to avoid males that matched themselves for MUP type, but females showed no avoidance of males that matched for MHC type. A small pilot experiment investigated the physiological effects of female social environment. Housing with unfamiliar females resulted in short-term decreases in female body mass and urinary protein concentration but an increase in urinary creatinine concentration. Competition between unfamiliar females may have resulted in a decreased water uptake and an increase in scent marking which could explain the physiological changes observed. Together these results suggest that female house mice may use two mechanisms of kin recognition. For social partner choice females may use a match-to-maternal MHC and MUP type mechanism, whilst for inbreeding avoidance females may use a match-to-own MUP type mechanism. The possibility of a single species using two separate mechanisms suggests that kin recognition may be considerably more complex than previously thought.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:592773 |
| Date | January 2012 |
| Creators | Holmes, Andrew |
| Contributors | Hurst, Jane; Beynon, Rob |
| Publisher | University of Liverpool |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://livrepository.liverpool.ac.uk/9259/ |
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