try a glas of wine before yo take on the calculator LOL it helps me!
White Rock x Buff Orpington?
- Thread starter soldieratheart
- Start date
How will they be auto-sexing? What will be the difference?
There are certain breeds which are known as autosexing breeds. One of the early giants of genetics, Prof Punnett of Cambridge University, found that when the barring gene was put onto certain e-alleles the chick down of these birds exhibited sexual dimorphism at hatch yet the adults bred true. He set about developing certain breeds which are considered the autosexing breeds.
Sex linked crosses, also, if my memory serves, found by Punnett & or Bateson. Used the dominant & recessive genes found on the Z sex chromosome to cause sexual dimorphism of chicks at hatch, (but the chicks themselves will not breed true when mature).
For instance, the presence of the sex linked barring gene on the Z sex chromosome, shows as a head spot on otherwise mainly black chicks. If one crosses coloured male onto a black barred female, all of the female offspring inherit their only Z sex chromosome from their father. They cannot inherit a barring gene; they have no head spot. The male offspring from the cross inherit one Z sex chromosome from their father (no barring gene) & also a Z sex chromosome from their mother; the Z chromosome from the barred mother has a barring gene. Thus all male offspring show the white headspot indicating the presence of barring.
There are quite a few other genes on the Z chromosome. Another widely gene sex linked cross works on the gold/silver sex linked alleles.
There are certain breeds which are known as autosexing breeds. One of the early giants of genetics, Prof Punnett of Cambridge University, found that when the barring gene was put onto certain e-alleles the chick down of these birds exhibited sexual dimorphism at hatch yet the adults bred true. He set about developing certain breeds which are considered the autosexing breeds.
Sex linked crosses, also, if my memory serves, found by Punnett & or Bateson. Used the dominant & recessive genes found on the Z sex chromosome to cause sexual dimorphism of chicks at hatch, (but the chicks themselves will not breed true when mature).
For instance, the presence of the sex linked barring gene on the Z sex chromosome, shows as a head spot on otherwise mainly black chicks. If one crosses coloured male onto a black barred female, all of the female offspring inherit their only Z sex chromosome from their father. They cannot inherit a barring gene; they have no head spot. The male offspring from the cross inherit one Z sex chromosome from their father (no barring gene) & also a Z sex chromosome from their mother; the Z chromosome from the barred mother has a barring gene. Thus all male offspring show the white headspot indicating the presence of barring.
There are quite a few other genes on the Z chromosome. Another widely gene sex linked cross works on the gold/silver sex linked alleles.
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