Biology 1001A Chapter 11.2: Cycle 5 - Sex-Linked Genes

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amethystarmadillo903

26 Jan 2018

School

Western University

Department

Biology

Course

Biology 1001A

Professor

Beth Mac Dougall Shackleton Tom Haffie

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Document Summary

Sex-linked genes: genes located on a sex chromosome: these genes are inherited differently in males and females. linked when considering two or more genes means that those genes are on same chromosome. Autosomes: chromosome other than a sex chromosome: these genes have same patterns of inheritance in both sexes. 11. 2a females are xx and males are xy: x chromosome occurs paired in female cells and single in male cells, y chromosome has short region of homology with x that allows them to pair in meiosis. In some insects, xx are females and xo (o means no y chromosome) are males. In birds, butterflies, some reptiles, males have homologous pair zz and females have zw. 11. 2b human sex determination depends on sry gene. Sex chromosomes are not especially associated with sexual organs or activity: many genes needed by both sexes are coded on x chromosome (ex.

Related Questions

11) CIRCLE ALL CORRECT ANSWERS: Human males are hemizygous for

a) Sxl gene b) pseudoautosomal region of the Y c)SRY d) gene for testis determining factor e) Xist gene

12) The X inactivation center codes for

a) gonadal ridges to form ovaries b) gonadal ridges to form testes c) RNA d) testosterone e) protein enhancing transcription of sex linked genes

13) CIRCLE ALL CORRECT ANSWERS: The pseudoautosomal region is found on

a) autosomes in males b) autosomes in females c) X chromosome d) Y chromosome e) both the X and Y chromosome f) could occur in fruit flies

14) Comparing two monozygotic XX twins to two monozygotic XY twins

a) XX are more identical b) XY are more identical c) monozygotic twins do not occur

EXPLAIN YOUR ANSWER:

15) CIRCLE ALL CORRECT ANSWERS: Butterflies and Habrobracon differ in

a) which sex is homogametic b) which sex is monoploid c) one has sex chromosomes and the other does not d) one produces some gametes by mitosis, the other does not

According to the multiplication rule of probability, the chance of crossing two pea plants that are heterozygous for height and have none of four offspring showing the recessive short phenotype is:A. Â¼ Ã Â¼ Ã Â¼ Ã Â¼.

B. Â¾ Ã Â¾ Ã Â¾ Ã Â¾.

C. (Â¼ Ã Â¼ Ã Â¼ Ã Â¼) + (Â¾ Ã Â¾ Ã Â¾ Ã Â¾).

D. Â¼ + Â¼ + Â¼ + Â¼.

E. None of the above.

What characteristic is exhibited by an X-linked trait?

a) Only females have the trait.

Females inherit X-linked traits from their maternal parent only.

c) Females can inherit a gene for an X-linked trait from either parent.

d) Males inherit X-linked traits from their paternal parent only.

e) Males can inherit a gene for an X-linked trait from either parent but normally inherit it from their fathers.

What characteristic is exhibited by a Y-linked trait?

		a) Y-linked traits appear only in male offspring of men with the trait.
		b)Y-linked traits are only passed from father to son.
		c) Y-linked traits can be passed from mother to son.
		d) Both A and B are characteristics of Y-linked traits.
		e) Both A and C are characteristics of Y-linked traits.

Which of the following codes for a phenotypic human male?

		a) XO with a copy of SRY gene on an autosomal chromosome?
		b) XXYY with one copy of the SRY gene deleted?
		c) XX with a copy of SRY gene on an autosomal chromosome?
		d) All of the above sex compliments results in a person with a sex phenotype of male.
		e) XY with the SRY gene located on an autosomal chromosome?

In Drosophila, yellow body is due to an X-linked gene (X^y) that is recessive to the gene for gray body (X⁺). A homozygous gray female is crossed with a yellow male. What are the genotypes of the F₁ progeny?

In some goats, the presence of horns is produced by an autosomal gene that is dominant in males and recessive in females. A horned female is crossed with a hornless male. The F₁ offspring are intercrossed to produce the F₂. What proportion of the F₂ females will have horns?

		a)1/2
		b)3/4
		c)1/4
		d) All
		None

a)		Females are X⁺X⁺; males are X⁺Y.
		b)Females are X⁺X⁺; males are X^yX^y.
		c)Females are X⁺X⁺; males are X^yY.
		d) Females are X⁺X^y; males are X^yY.
		e) Females are X⁺X^y; males are X⁺Y.

	Females inherit X-linked traits from their maternal parent only.
		Females can inherit a gene for an X-linked trait from either parent.
		Males inherit X-linked traits from their paternal parent only.
		Males can inherit a gene for an X-linked trait from either parent but normally inherit it from their fathers.