Question

In: Biology

Consider the gene for the character “freckles”. We’ll use “F” to designate the dominant allele (which...

Consider the gene for the character “freckles”. We’ll use “F” to designate the dominant allele (which produces freckles), and “f” to designate the recessive allele (no freckles).

a. Suppose one parent has freckles. What are the possible genotypes for that parent? ____________________

b. Suppose one parent has no freckles. What do we know about that parent’s genotype? ___________________

c. If the parent with freckles is homozygous (FF), what proportion of offspring will have freckles?

A) None of them

B) 25%

C) 50%

D) All of them

d. If an offspring with no freckles is produced, what do we know about the genotypes of the parents, supposing that both have freckles? ___________________________________________________________________

Suppose I have 2 flowering trees, one that produces yellow flowers, while the other produces blue flowers. Moreover, I learn that each tree is true-breeding, i.e., it is homozygous for flower color. Then I perform a cross between the trees, i.e., interbreed them.

a. Suppose all of the offspring trees produce greenish (intermediate between blue and yellow) flowers. What kind of relationship between the alleles is indicated? _______________________________________

b. Suppose the offspring trees all have some yellow and some blue flowers. What relationship between the alleles is indicated? _____________________________________________

A gene can have only 1 specific phenotypic effect.TrueFalse

A gene having more than 1 phenotypic effect is called _______________________________.

Some characters (such as height and skin color) are known as quantitative characters. What does this mean? Give an example of a quantitative character.

Expert Solution

a. FF or Ff

b. ff

c. all of them as the genotypes of offsprings will either be FF or Ff.

d. If no freckled offsprings are produced that means that both the parents are heterozygous i.e they will have Ff genotypes.

Ff x Ff

	F	f
F	FF	Ff
f	Ff	ff

a. BB X bb

blue x yellow

	B	B
b	Bb	Bb
b	Bb	Bb

all green. This shows incomplete dominance.

b. Bb x Bb

B

b

B

BB

blue

Bb

green

b

Bb

green

bb

yellow

In incomplete dominance, both alleles affect the trait additively, and the phenotype of the heterozygote is intermediate between either of the homozygotes.

False- a gene can have the pleiotropic effect that is it can affect many traits.

A gene having more than 1 phenotypic effect is called the pleiotropic effect.

A quantitative trait is a measurable phenotype that depends on the cumulative actions of many genes and the environment. These traits can vary among individuals, over a range, to produce a continuous distribution of phenotypes. Examples include height, weight and blood pressure.

gladiator answered 11 months ago

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