6) A long winged male crow with a head ruff mates with a short winged crow witho

Question

6) A long winged male crow with a head ruff mates with a short winged crow without a head ruff. All of their male offspring have long wings, half of them have a head ruff and half lack a head ruff. All of the female offspring have long wings and half have a head ruff and half do not. A) Are either of these genes sex-linked? B) What is your reasoning? C) What is the most likely genotype for each parent and type of offspring? (4 pts)

What would be a key for this problem

Long winged male crow

Head ruff

Short winged female crow

No head ruff

Is this the correct way to do this and Are either of these genes sexed linked

What is your reasoning

Genotype for parents

Long winged male crow with a head ruff = ZLrZLR

Short winged female crow without a head ruff = ZlrW

Genotype for offsprings

½ Male offspring have long wings and a head ruff   = ZLRZlr

½ Male offspring have long wings without a head ruff = ZLrZlr

½ Female offspring have long wings and a head ruff = ZLRW

½ Female offspring have long wings without a head ruff = ZLrW

ZLr

ZLR

Zlr

ZLrZlr

ZLRZlr

W

ZLrW

ZLRW

Are either of these genes sexed linked

What is your reasoning

Ask this question several times still do not understand how do you know is? Is there a way to explain it in everyday words.

10) Hunchback serves as a silencer protein for the gene encoding Ultrabithorax. A) Which of these two genes is epistatic to the other? B) How do you know? received several scientific answers that I do not understand.

Epistasis is a form of gene interaction in which one pair of genes masks or hides the phenotypic expression of another. Hunchback (hb) gene is epistatic to Ultrabithorax (Ubx) gene.

Thank you very much. I would appreciate it if you can answer both. Do not have many questions remaining to ask for the month.  

ZLr

ZLR

Zlr

ZLrZlr

ZLRZlr

W

ZLrW

ZLRW

Explanation / Answer

The genes for long wings are sex-linked. The father crow is homozygous for this gene.

Reason -  

Father has XY chromosomes. All the male offsprings inherit the Y-chromosome from the father and the X-chromosome from mother.

All the female offsprings have XXchromosomes of which one X- chromosome is inherited from father and one from mother.

Since all the offsprings have long wings, it means that the gene for long wings is present on the XY chromosomes and the father crow is homozygous for that gene.

The gene for long wings is dominant and is present on both the X and the Y chromosome of the father.

This is the reason for all the offsprings having long wings.

The genes for head ruff are not sex-linked. The father crow is heterozygous for this gene and the mother is homozygous recessive for this gene.

Reason--

f the gene had been present on the father's Y-chromosome then all the male offsprings would have got head ruff but only half of them have got so.

Likewise, if the gene had been present on the X-chromosome of the father then all the female offsprings would have inherited it and got the head ruff.

The gene for head ruff is not present on the mothers X- chromosome because she does not have the head ruff. So, either she is homozygous recessive for the gene controlling head ruff or does not have those genes.

This explains the reason why all the offsprings have long wings but only half of each male and female offsprings have the head ruff.

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