BIO220H1 Lecture Notes - Lecture 11: Inbreeding Avoidance, Inbreeding Depression, Allosome

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pinkworm736

28 Oct 2012

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BIO220H1 Full Course Notes

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Sex chromosomes: layering of genetic material, moth females often have a w chromosome. Autosomes: high and low levels of recombination, all population members will have these autosomes. We can use mtdna to track maternal lineage. We can use y chromosome to track paternal lineages. Observations: elephants: fluid social system females live in small groups with other related females from their maternal lineage, males do not join other groups, males can detect females ready to reproduce from far distances. Can be attracted to females that live in a group from which they belong. Males will still reproduce when their daughters are mature. Yes because inbreeding depression is very severe --viability and survival of offspring is much less compared to non-inbred offspring. We cannot do experiments on elephants because they are not good models, however we can use genetic markers. What ecological force leads to differentiation? were born.

Related Questions

Why are recessive X-linked traits seen more often in human malesthan in human females? (Select all that apply.)

Males have an X chromosome, but females do not.

Actually, X-linked traits are seen more often in females than inmales, because they have two X chromosomes.

Males donât have a second X chromosome to mask the effects ofthe first one.

This phenomenon is due to X-inactivation.

While females would need two of these alleles to express therecessive phenotype, males only need one.

Sperm are more likely to carry an X chromosome than a Ychromosome.

jadebee948

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.

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

lilacmallard101

How do we know that Drosophila utilizes a different sex-determination mechanism than mammals, even though it has the same sex-chromosome compositions in males and females?

Check all that apply

XXY flies being female (given the normal set of autosomes) implies that that the critical factor in sex determination is the ratio of X chromosomes to the number of haploid sets of autosomes.

XO flies being male (given the normal set of autosomes) implies that that the critical factor in sex determination is the ratio of X chromosomes to the number of haploid sets of autosomes.

XO flies being female (given the normal set of autosomes) implies that that the critical factor in sex determination is the ratio of X chromosomes to the number of haploid sets of autosomes.

XXY flies being male (given the normal set of autosomes) implies that that the critical factor in sex determination is the ratio of X chromosomes to the number of haploid sets of autosomes.