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#115947 - 07/30/16 02:31 AM Ie mutation, Yellow-legged Blacks 1953 article
KazJaps Offline
Classroom Professor

Registered: 08/30/02
Posts: 2864
Loc: Australia
This is an old Australian veterinary magazine called "Centaur", issue No 15, published 1953.
Google link to pdf, automatic download (25.5 MB file)

See the included article pages 23 to 25 (pages 25 to 27 in pdf):
Author ? I.D. Smith II

For a 1953 article, it is very good with up to date genetic terms of Id, E, W loci noted, plus epidermal & dermal pigments. The author experienced in Exhibition double-mating of Black Leghorns & Wyandottes, undertook test breeding & noted an incompletely dominant mutation (noted probably autosomal) that removed epidermal pigment from E, plus bleached some plumage feathers in males, in pullet-line yellow-legged Black Leghorns. He named the mutation Ie (Inhibitor of Epidermal melanin), & noted it had different effects on males & females depending on whether heterozygous or homozygous (sex influenced).

It's a shame this article wasn't picked up by USA & UK poultry geneticists.

Edited by KazJaps (08/03/17 07:10 PM)
Edit Reason: fixed broken image link

#115948 - 07/30/16 04:08 AM Re: Ie mutation, Yellow-legged Blacks 1953 article [Re: KazJaps]
Redcap Offline
Ruler of the Roost

Registered: 08/14/06
Posts: 984
Loc: Germany
I just have to answer in a free translated german saying
You can get old like a cow, You never can say, I have learned out now.

#115957 - 08/07/16 05:30 AM Re: Ie mutation, Yellow-legged Blacks 1953 article [Re: Redcap]
mibirder Offline

Registered: 07/06/11
Posts: 67
Loc: Michigan, USA
Has/was Smith's Ie mutation standardized into the current shank color genetic thing ( in addition to W and Id) or has his results been incorporated into the understanding of Id?

#115967 - 08/08/16 06:20 PM Re: Ie mutation, Yellow-legged Blacks 1953 article [Re: mibirder]
KazJaps Offline
Classroom Professor

Registered: 08/30/02
Posts: 2864
Loc: Australia
Smith was referring to a separate mutation that removes epidermal pigment in E extended blacks. Id (by itself) doesn't remove this epidermal pigment. Although the E mutation also produces some dermal pigment.

I haven't seen poultry geneticists refer to Smith's Ie test breeding article. The article was published in an Australian veterinary magazine in the 1950's, so it may never have come to attention to geneticists in other countries.

There have been other articles on breeding exhibition yellow-legged blacks (eg Sturges), some suggesting some lines were eb based (eg segregating from Silver-laced Wyandottes). Smith's were E (or ER) based, as he describes the chick down as the following:
The chicks of black breeds have black down at hatching, but show varying degrees of white, yellow or grey on the ventral surface.

Fred Jeffrey in his book "Bantam Breeding & Genetics" (also published as "Bantam Chickens") discusses Cote's (1976) test breeding results on solid eumelanin roosters. In particular, a Blue Frizzle (Cochin) rooster: E/E Id/Id ml+/ml+

Page 156:
This unusual yellow-legged Blue when mated with a Light Brown Leghorn (yellow shanks) produced progeny with "willow" shanks -- not dermal pigment. These results suggest that there are other genes than melanotic which can restrict pigment in the epidermis of the shank.

For some reason, some believed that the Ml melanotic mutation was responsible for the removal of shank epidermal pigment in yellow-legged blacks, & bleaching of male plumage undercolour. But, ER based yellow-legged non melanised varieties exist (eg Birchen Grey, Brown Reds, etc) & obviously melanisers (apart from E or ER) are not in these.


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