Question

In humans, sex determination involves what mechanism?

Group of answer choices

An X-chromosome mechanism

A Y-chromosome mechanism

An autosomal genic mechanism

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Question 251 pts

The SRY gene is located on:

Group of answer choices

The X chromosome

The Y chromosome

An autosome

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Question 261 pts

In birds, females are characterized by which karyotype?

Group of answer choices

XY

XX

ZW

ZZ

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Question 271 pts

The white eyes w gene of Drosophila is located on the X chromosome. A fly will be ‘hemizygous’ for the w gene if it has which karyotype?

Group of answer choices

XX

XXY

XY

Answer 1

Question - 1, 2nd is correct option because in human, presence or absence of Y chromosomes determine sex. If Y is present, male form and if Y is absent , female form.

Question - 251, SRY region is located on Y chromosome so 2nd is correct option.

Question - 261, In birds, male are homozygous and female are heterozygous. Male karyotype remain ZZ and female ZW so 3rd one is correct answer.

Question - 271, hemizygous means only one chromosome of that type is present, there is no chance of being homozygous or heterozygous for that chromosome. So 3rd one is correct as one X is present in this.