Phenotype (male-magnificent feathers) polymorphism is controlled by one supergene

“Alice laughed. ‘There’s no use trying. One can’t believe impossible things.’  I daresay you haven’t had much practice,’ said the Queen. ‘When I was your age, I always did it for half-an-hour a day. Why, sometimes I’ve believed as many as six impossible things before breakfast.”  –––Lewis Carroll, Through the Looking-Glass and What Alice Found There  (1871).

The same thing is true in genetic expression of various genomes.  It seems that almost anything is possible. For example, the (really cool) articles referenced below show how highly divergent modes of male reproduction in a wading bird are controlled by alternate alleles at a single locus––encompassing a 4.5-Mb inversion in the genome. The locus is an example of a ‘supergene’ that controls multiple complex phenotypes.

Authors demonstrate that development into satellites and faeders is determined by a supergene––consisting of divergent alternative dominant and non-recombining haplotypes of an inversion on chromosome 11––which contains 125 predicted genes. One breakpoint of the inversion disrupts the essential CENP-N gene (encoding centromere protein N), and pedigree analysis confirms the lethality of homozygosity for the inversion. They also describe new differences in behavior, testis size, and steroid metabolism, among the polymorphs and identify polymorphic genes within the inversion that are likely to contribute to the differences among morphs in reproductive traits.

 Nat Genet Jan 2o16; 48: 79–83  &  7–8

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