Please can you help! genetics "Mendel": You are studying genetics in domestic chickens (Gallus gallus) and you find a mutant with no wings. Assume that the mutant wingless phenotype is due to a mutation at a single gene.
In contrast to mammals, chickens use ZZ/ZW sex-linkage. That is, male chickens have two copies of the sex chromosome, the Z chromosome, while females have one copy of Z and one copy of W. The W is like the Y in mammals; it carries very few genes.
You should use the following symbols in this problem:
• If the gene is autosomal, use:
• “A” for the allele with the dominant phenotype
• “a” for the allele with the recessive phenotype
• If the gene is sex-linked (Z-linked) use:
• “ZA” for the allele with the dominant phenotype
• “Za” for the allele with the recessive phenotype
• “W” for the W-chromosome:
• a) You cross a pure breeding male with normal wings to a pure breeding wingless female. All of the F1 offspring have normal wings. Based on this result, which of the following statements is true:
a-) Therefore Cross of Parent AA X aa or ZAZA X ZaW therefore
The normal wing phenotype is dominant; the wingless phenotype is recessive.
Please help me with part b?
• b) You cross an F1 male to an F1 female (both phenotypically normal-winged). In their 400 offspring, you see a 3:1 ratio of normal to wingless. Upon closer examination, you find that all the wingless chickens are female. Based on these data:
• i) Is the wingless gene autosomal or Z-linked?
• ii) What is the genotype of the normal-winged F1 male parent of the cross? (AA, Aa, aa, A_, ZAZA, ZAZa, ZaZa, ZAZ, ZAW, or ZaW)
• iii) What is the genotype of the normal-winged F1 female parent of the cross? (AA, Aa, aa, A_, ZAZA, ZAZa, ZaZa, ZAZ, ZAW, or ZaW)
• iv) What is the genotype of the wingless female offspring of the cross? (AA, Aa, aa, A_, ZAZA, ZAZa, ZaZa, ZAZ, ZAW, or ZaW).
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Thanks Blue; Question b-1) assuming xlinked then my solution which I am not sure is that the Female Parent is Recessive ZAW Cross with male ZAZa First generation crosss which then bii) I got ZAZa 1/4 then biii)ZAW and finally BiV) ZaW Please check!
all of the 1/4:1/4:1/4:1/4 ZAZA, ZAW, ZAZa, ZaW
OK, so the ZA, ZAW, all that stuff is genotypes. They are a notation for what sex chromosome (the W sex chromosome, when present, making the chicken be female - or the Z chromosome, when two are present, making the chicken be male).
It tells you the notations.
The Za is a Z sex chromosome with a recessive allele for the trait of interest. Z indicates the Z chromosome, lowercase a indicates the recessive allele.
ZA is the Z sex chromosome with a dominant allele for the trait of interest. Again, Z indicates that we are talking about a Z chromosome, the uppercase Z indicates the dominant allele.
And the W indicates the W chromosome, which never has any alleles on it.
You explained clearly but the above given they defined Zwith capital A as Dominant and ZZ capital as the Male crock and Female as big capital Z with Small a with W which W standa (mamaly Y) Assuming that it is not autosomal then Zlinked we can cross F1 Zon top big A (ZA)ZA which are New Parent Male with Female ZAW? does this sound way forward
There is z lower case at all on the given boundries that ZA which is (X for mamals) and W (Y for Mamals) Felame ZaW recessive and male ZAZa Dominant at F1 new cross Part b becouse Original Parents As you expalined part a solution so part b is what need your help!
You are confused about the parents genotypes
It says that you cross a normal male with an abnormal female.
So the male has two Z chromosomes, and because is is pure breeding normal, we know that both his alleles are dominant. So he must be ZA ZA.
The female has one Z and one W. We know this because she is female. But she is a mutant, which means her Z must have the recessive allele. So her genotype is Za W.
To sum up, the parents genotpyes:
Dad: ZA ZA
Mom: Za W
clear on that
When it talks about the F1 generation, it means the offspring that came from crossing Mom with Dad. So what offspring are there?
Dead is ZAZa cross with Female ZAW when I was Typping made the mistake!
So those are the F1 genotypes. You take one of these males, who are ZA Za, and you cross it with a female, which is ZA W.
You're welcome. I'm glad that I could help.
Please Blue can You Help me part C!
c) You also examine the inheritance of feather texture (rough or silky) and feather color (brown or white). You know that neither of these traits is sex-linked. You do the following cross:
a pure breeding male with rough white feathers X
a pure breeding female with silky brown feathers
The F1 chickens have rough brown feathers
Use the upper case letter for the allele associated with the dominant phenotype and the lower case letter for the allele associated with the recessive phenotype. Texture: rough or silky, use the notation T or t. Color: brown or white use the notation C or c.
Based on these data:
i) What is the genotype of the pure-breeding male with rough white feathers?