Wow that is very helpful! How the heck would we determine which are split for buff though[SIZE=12pt][SIZE=12pt]Hi Aoxa - here's an extract from an article that I prepared for the Sebastopol Geese Lovers Forum with a chart you can refer to - hope it helps you[/SIZE][/SIZE]
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[SIZE=12pt][SIZE=12pt]Pete[/SIZE][/SIZE]
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[SIZE=12pt][SIZE=12pt]In Geese the sex chromosomes can actually influence the phenotype of the bird as some of the genes for colour and pattern are sex-linked. For example the gene responsible for Buff is carried on the male chromosome only. To further complicate matters, in birds the sex chromosomes act differently than in most other mammals including ourselves.[/SIZE][/SIZE]
[SIZE=12pt][SIZE=12pt]In humans the sex of a child is determined by the father’s sperm. The genetic code being XY which means there are either X sperm or Y sperm. In females the genetic code is XX which means there are only X eggs. Therefore in an X egg combines with an X sperm then the code will be XX meaning a female. If another X egg combines with a Y sperm then the code will be XY – a male.[/SIZE][/SIZE]
[SIZE=12pt][SIZE=12pt]In birds the sex chromosomes are coded Z and W but act in an opposite manner to ourselves. In a Gander their genetic code for sex is ZZ and in a Goose their code is ZW. So in the case of our geese it is the female which selects the sex of the offspring. Her eggs are either Z or W in equal ratios. The male can only produce Z sperm. So if the Z sperm fertilises a Z egg then a male will result and if the Z sperm fertilises a W egg then a female will result.[/SIZE][/SIZE][SIZE=12pt]The Buff gene is a recessive sex linked genes. This means that it is carried on the Z sex chromosome. In order to show visually all the bird’s Z chromosomes must carry a recessive form of this gene. So in the case of a female whose genotype for sex is ZW then only one recessive gene that is linked to the Z chromosome is required for the effect to show visually. In the case of a male with two Z chromosomes then both genes must carry the recessive gene for the effect to show visually. If only one of the Z chromosomes carries a recessive gene then the male will carry (or be ‘split’ for) the recessive gene in its genotype but its phenotype remains the same. Using the Buff gene (G) as an example the genotype can be written and its phenotype interpreted.[/SIZE]
[SIZE=12pt]Z,Z, G, G (normal male) – visually Grey[/SIZE]
[SIZE=12pt]Z, Z, G, g (male split for buff) – visual grey but carries the recessive buff gene (g).[/SIZE]
[SIZE=12pt]Z, Z, g, g (buff male) – visually buff as both Z chromosomes have the recessive gene (g, g).[/SIZE]
[SIZE=12pt]Z, W, G (normal female) – visually grey.[/SIZE]
[SIZE=12pt]Z, W, g (buff female) – visual buff as the only Z chromosome has the recessive gene (g).[/SIZE]
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He had given up on the male and switched the girls back to the grey ganders so not to waste any more of the breeding season. My two girls were a sign that the buff gander actually DID get the girls. He said he did one batch of eggs and none were fertile, so he pulled the male.
I'd rather have grey than no dewlap toulouse at all. I will end up purchasing a gander either way. Whether it be buff
fl) or grey.
