tag:blogger.com,1999:blog-8278510471239667560.post5931287066194722457..comments2024-03-27T19:59:10.159+00:00Comments on Kensington Gardens and Hyde Park birds: Ralph Hancockhttp://www.blogger.com/profile/11686354797977020917noreply@blogger.comBlogger2125tag:blogger.com,1999:blog-8278510471239667560.post-85227578330841797772013-03-19T12:02:50.995+00:002013-03-19T12:02:50.995+00:00Thanks very much for this interesting information....Thanks very much for this interesting information. The site you mention is excellent and has cleared up a lot of things I was wondering about.Ralph Hancockhttps://www.blogger.com/profile/11686354797977020917noreply@blogger.comtag:blogger.com,1999:blog-8278510471239667560.post-82269921100720770462013-03-19T10:31:46.144+00:002013-03-19T10:31:46.144+00:00Dear Ralph,
I was intrigued by your musings on ma...Dear Ralph,<br /><br />I was intrigued by your musings on mallard colourations! There is a good site from the web which deals with duck genetics in relation to colour and patterning. Essentially the developmental and biochemical processes are similar in birds and mammals, with the exception being sex linked traits. In most mammals (with the notable exception of duck billed platypus which lays eggs and has a beak like structure) the male on X and one Y chromosome, the female has two X chromosomes. In birds it is the other way around, the male has two Z chromosomes, the female has one Z and one W chromosome. Some of the sex linked colourations such as the "diluted brown" gene causes a reduction in pigmentation is recessive and carried on the Z chromosome, and so ismuch more common in females than males, in the same way mammalian colour blindness is more common in males than females.<br /><br />http://www.backyardchickens.com/t/410593/understanding-basic-colour-genetics-mallards-derivitives<br /><br />Other factors such as neural crest migration problems which result in a failure of melanocytes to reach the dermis are also involved, and are the basis for piebaldness. Environmental and seasonal or circadian factors are also involved.<br /><br />The blog is great and I check it daily as I am unable to visit the site as often as I would like.<br /><br />all the best<br /><br />Andy SuntersAnonymousnoreply@blogger.com