(1) \"If two genes are linked, then the expected phenotypic ratio resulting from
ID: 94459 • Letter: #
Question
(1) "If two genes are linked, then the expected phenotypic ratio resulting from a testcross would be"
9:3:3:1
1:1:1:1
1:01
no correct answer
1:02:01
(2) The penetrance and expressivity of a gene depend on
xenotype
sex influences
both A and B
neither A or B
(3)
In chicken males, genes on the Z chromosome are
heterogametic
hemizygous
homozygous
homogametic
heterozygous
(4)
A fruit fly with the genotype XXYY would be phenotypically
either male or female
male
female
both male and female
1.9:3:3:1
2.1:1:1:1
3.1:01
4.no correct answer
5.1:02:01
Explanation / Answer
(1) "If two genes are linked, then the expected phenotypic ratio resulting from a testcross would be"
The answer is 4. No correct answer
As said in the question, when the genes are linked, they try to inherit together, there is no chance of recombination. So the resulting offspring will be more of parental type and less of recombinant type.
(2) The penetrance and expressivity of a gene depend on
Answer is C. both A and B
It is both environmental influence and genotype which determines the penetrance and expressivity of a gene.
(3) In chicken males, genes on the Z chromosome are
Answer is 4.homogametic
In the case of chicken, the Males are the homogametic sex (ZZ), while females are the heterogametic sex (ZW).
(4) A fruit fly with the genotype XXYY would be phenotypically
The answer is 2. Male
Because of the presence of Y chromosomes, the fly with genotype XXYY will look like a male phenotypically.
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