Codominance in Chickens

[black_cat]

Hi all!
In school, I'm learning about codominant genes. Are BBS genetics an example of codominant genes? If so, what colorings are?
Thank you for the help!

 

[SourRoses]

This is a really good question to help everyone learn more!

@NatJ
@nicalandia

 

[nicalandia]

Hi all!
In school, I'm learning about codominant genes. Are BBS genetics an example of codominant genes? If so, what colorings are?
Thank you for the help!

No, blue BBS is whats called Incomplete Dominance. Look for the Paint phenotype for codominant gene

 

[black_cat]

No, blue BBS is whats called Incomplete Dominance. Look for the Paint phenotype for codominant gene

View attachment 3455786

Thank you! Would splash be considered codominance or is there something else at play? If so, how does that work?

 

[pipdzipdnreadytogo]

No, Splash is simply the full dilution effect of the gene. In partial (or incomplete) dominance, as the flower picture shows above, the heterozygous individual shows a mixture of both homozygous possibilities for that gene. So a homozygote with the blue gene, Bl/Bl, is Splash, a grayish white color, while a homozygote without the blue gene, bl+/bl+, is Black. A heterozygous individual (Bl/bl+) meanwhile is a color in between the two homozygous versions, blue-gray.

An individual heterozygous for a codominant gene shows a bit of both the homozygous versions, not a color in between, as the flower picture demonstrates. So for example the Paint or Erminette pattern is based on codominance with the dominant white gene on a solid black base. With these patterns, a homozygous individual for dominant white (I/I) is solid White, and an individual homozygous without dominant white (i+/i+) is solid Black. The heterozygous individual (I/i+) is not a gray color in between the homozygous colors like in partial dominance, but instead an individual who is white with some black patches. So a little bit of both homozygous colors shows up without either color being tinted or diluted by the other color. Does that make sense?

Edited for clarity​

 

[black_cat]

No, Splash is simply the full dilution effect of the gene. In partial dominance, as the flower picture shows above, the heterozygous individual shows a mixture of both homozygous possibilities for that gene. So a homozygote with the blue gene, Bl/Bl, is Splash, a grayish white color, while a homozygote without the blue gene, bl+/bl+, is Black. A heterozygous individual (Bl/bl+) meanwhile is a color in between the two homozygous versions, blue-gray.

An individual heterozygous for a codominant gene shows a bit of both the homozygous versions, not a color in between, as the flower picture demonstrates. So for example the Paint or Erminette pattern is based on codominance with the dominant white gene on a solid black base. With these patterns, a homozygous individual for dominant white (I/I) is solid White, and an individual homozygous without dominant white (i+/i+) is solid Black. The heterozygous individual (I/i+) is not a gray color in between the homozygous colors like in partial dominance, but instead an individual who is white with some black patches. So a little bit of both homozygous colors shows up without either color being tinted or diluted by the other color. Does that make sense?

Edited for clarity​

Yes, it does. Thank you!

 

[Saveria]

You all are so smart.