University of St Andrews
Sea Mammal Research Unit
SMRU > Research > Genetics


Genetics is the study of characteristics that are passed from one generation to the next and various molecular methods can be used to determine genetic variation among populations.  Related individuals share many of the same genes but individuals in another group or population may have lost some of these common genes. Genetic analysis can therefore be used to distinguish one population from another, to estimate the frequency of interbreeding between populations, to investigate the ancestry and relatedness of different individuals within populations and to determine breeding and mating strategies.  All populations have some diversity within the collective gene pool, without which, a population is vulnerable to disease or changes in its environment.  Some marine mammal species, whose populations have been reduced to very low numbers, may have lost some of this important genetic diversity.


Two main approaches have been applied to studies of genetic variation in marine mammals.

DNA sequencing, usually involving investigating mitochondrial DNA (mtDNA) since it evolved very rapidly and so even closely related species have distinct differences.  This is used to explore differences among species, sub-species and geographically distinct populations.

Microsatellite analysis involves investigating the occurrence of tandem repeat DNA motifs that can be replicated hundreds or thousands of times within an individual.  These repeats show extreme levels of polymorphism, carrying 5 to 10 alleles per locus and can be used to identify individuals and investigate parentage as well as detect differences between populations and species.


Paddy Pomeroy has collaborated with others to investigate grey seal breeding patterns. The relationships between pupping site choice, reproductive success and mate choice, and their consequences for genetic structure within breeding colonies have been studied.   The effects of potential inter-relatedness on fitness and offspring survival  have been investigated by Ian Boyd.

Ailsa Hall has been collaborating with the molecular biology group in the School of Biology to determine the population structure and genetic diversity of harbour seals around the UK.
DNA sequencing is used to investigate geographical variation



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