PHENOTYPIC VARIATION IN ROCK POCKET MOUSE: WHAT LIES BENEATH

Running head: PHENOTYPIC VARIATION IN ROCK POCKET MOUSE: WHAT LIES
BENEATH?
PHENOTYPIC VARIATION IN ROCK POCKET MOUSE: WHAT LIES BENEATH?
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PHENOTYPIC VARIATION IN ROCK POCKET MOUSE: WHAT LIES BENEATH?
A primary objective of evolutionary biology is to elucidate and explore the variation
in morphology that exists across species. Genetic variation represents the range of genetic
differences in a population. Natural selection influences the genetic variation of a species in a
way which can affect the frequency of gene variations, already present in the population
(Real 2017). Understanding the origins of such intraspecific deviation provides information
about the impact of local environment as a deciding factor for rapid evolution. Purpose of this
think piece is to highlight the underlying mechanism of genetic variation in causing habitat
specific adaptation in rock pocket mouse.
Contrary to the popular hypothesis that advocates phylogeny as a source of
phenotypic variation in a population, recent advances underline mutation and migration as
sources of genetic variation (McRobie, Moncrief and Mundy, 2019). On this context, the
extensive colour polymorphism exhibited by rock paper mice forms the centrepiece of this
discussion that aims to clarify the correlation between the location of habitat and evolution of
genetic variations over time in a single species.
Researchers have mainly been keen on studying the evolution of colour variances in
response to geographic conditions. The natural habitat of rock paper mouse is typically in
rocky regions across deserts, and hence their habitation is uneven. Various subspecies of
this mouse living in small isolated lava flows represent drastic body colour differences
among themselves. Mice populations from non-lava regions also display a difference in coat
colour, that often narrowly resembles the colour of the substrate on which they live
(Hoekstra, Krenz and Nachman 2005). Such disparities in colour cannot be merely
attributable to their phylogenic history, as evidence suggests, populations of a species connect
via recent ancestry, that is, a high gene flow or migration. Irrespective of an intense local
genetic flow, polymorphism in colour is highly associated with habitat colour, corroborating
the link of strong natural selection in this species and morphological diversity (Bernatchez