Conclusions and future research on the evolution and maintenance
of melanin-based colour polymorphism
Melanin-phenotypes represent phenotypic traits segregating in
melanin-based colour polymorphic organism. In this study we demonstrate
the colour phenotype in the tawny owl appears to be regulated by
non-exonic polymorphisms in genes not traditionally associated with
colour genes, perhaps like what has been reported for the barn owl (Luis
M. San-Jose et al., 2017). This is not necessarily surprising, with
quantitative differences in feather colour in the chicken also being
regulated in such non-traditional genes (Fogelholm et al., 2020).
Nevertheless, identifying genetic variation in regions responsible for
environmental-dependent biological functions that co-vary with
coloration is a step-forward to understand evolution and specially, the
maintenance of intra-specific colour polymorphism. Potential follow-up
work for this work would be to improve the screening density of the
tawny owl genome while also adding information using transcriptomic and
epigenetic sources to fully pin down the long theorized (genetic)
linkage between colour producing genes and melanin-phenotypes (Fig. 3).