Blue sparrow seen in Australia

In April, GrrlScientist posted a picture of a blue house sparrow seen in April among normal colored birds. She commented on the nature of its mutation.

Passer domesticus, var. blue

Passer domesticus, var. blue

Birds and butterflies aren’t blue because of pigment but because of their surface texture of their feathers or scales, so I’m guessing that this is a structural change in the feathers.

It would be very interesting to get the local university to put up a mist net, band their catch, and perhaps pluck a feather or two. I’m curious about the genetics of family members — I wonder if some of the brown ones are heterozygous for blue feathers and how many ordinary sparrows it would take to find out. And will the chicks dig it?

GrrlScientist has a follow-up and more photos from the one who spotted this bird in Sydney, Australia, in April.

Genetic analysis confirms pattern of sheep domestication

Manx Loaghtan sheep, from the Isle of Man, have 4 – 6 horns

Manx Loaghtan sheep, from the Isle of Man, have 4 – 6 horns

Blogger Abbie Smith at ERV has the story: “Bah bah black sheep, have you any ERVs?”.

The gist of it is that ERVs are viral genomes which read themselves into an individual’s DNA. If the infected cells are in the eggs or sperm, the ERV is passed on to all descendants, who have the same virus at a unique location in their chromosome.

ERVs mutate rapidly, which makes it possible to trace different lineages of the same original ERV and put them into a tree diagram showing who broke off first and who’s descended from the breakaway group vs. the original group.

The evidence thus gathered confirms historical evidence about the domestication of sheep in southwest Asia in two waves. In some remote places, farmers kept on breeding the older types. The details are interesting and the explanation is amusing.

%d bloggers like this: