Question

1.Which of the following is TRUE?

a) Genetics is about the genotype.

b)Inheritance is controlled by factors and each offspring receives three factors from each parent.

c)Allele pairs never segregate from one another.

d)The principle of segregation states that genes for different traits assort independently of one another in the formation of gametes.

e)Independent assortment of two traits shows a F2 generation that has a 9:3:3:1 phenotypic ratio.

2.A cross between a black rabbit (BB) and a white rabbit (bb) produces offspring with a mix of black and white fur. This is an example of

a)Incomplete dominance.

b)Codominance.

c)Polygenic inheritance.

d)Multiple alleles.

e)Nondominance.

3.How will “AaBb” align along the metaphase plate during meiosis I (assuming independent assortment)?

a)AA

aa

BB

bb

b)Aa

Bb

c)AA aa

BB bb

d)AA aa

bb BB

e) Both 3rd and 4th answer choice.

4. In a cross between AaBbCc and AabbCC, what is the probability of an offspring with the phenotype Dominant A, Dominant B, and Dominant C?

a)1/2

b)1

c)3/8

d)3/16

e)1/12

5.A red-eyed female Drosophila whose mother was white-eyed, is crossed with a red-eyed male. What is the phenotype of the offspring?

a)All white-eyed.

b)All red-eyed.

c)¾ red-eyed and ¼ white-eyed.

d)¾ white-eyed and ¼ red-eyed.

e)½ red-eyed and ½ white-eyed.

6.Which of the following is TRUE regarding McClintock’s and Creighton’s experiment with corn?

a)They used a pair of homologous chromosomes that were physically identical.

b)They showed that chromosomes do not physically exchange chromosomal material.

c)The experiment could only be verified cytologically, not phenotypically.

d)Only recombinant phenotypes appeared.

e)The recessive phenotype could only appear as a result of crossing over.

7.Which of the following is TRUE?

a)Linkage is 0% to 50%.

b)Genes that are far apart on the same chromosome are less likely to crossover.

c)One map unit = 100 cM.

d)For mapping, traits must be within 50% in theory.

e)Two traits 100% apart would end up together 0% of the time.

8.You cross a Drosophila AaBbCc (parents were AABBCC x aabbcc) with another Drosophilaaabbcc. You get the following phenotypes. Which gene is in the middle?

1000 offspring:

• 675 dominant ABC or recessive abc phenotypes
• 25 aBc or AbC
• 75 Abc or aBC
• 225 ABc or abC

a)A

b)B

c)C

9)A recombination frequency of 28% between two D. melanogaster genes suggests which of the following regarding their relative chromosomal locations?

a)They are located on two different chromosomes.

b)They are on the same chromosome, but not linked.

c)They are linked on the same chromosome.

d)They assort independently.

Recombination frequency does not provide information with respect to chromosome location.

Answer 1

1 e)Independent assortment of two traits shows an F2 generation that has a 9:3:3:1 phenotypic ratio.

2a. Incomplete dominance-

Incomplete dominance is when a dominant allele, or form of a gene, does not completely mask the effects of a recessive allele, and the organism's resulting physical appearance shows a blending of both alleles.

3.

4c. 3/8

. AaBbCc and AabbCC

Aa x Aa-

	A	a
A	AA	Aa
a	aA	aa

3/4 probability of being dominant

Bb x bb

	B	b
b	Bb	bb
b	Bb	bb

1/2 probability of being dominant

Cc x CC

	C	c
C	CC	Cc
C	CC	Cc

probability of being dominant - 1

Thus the overall probability of being dominnat= 3/4 x 1/2 x 1 =3/8

5.c)¾ red-eyed and ¼ white-eyed.

XEX x XEY

Red eyed female x red-eyed male

	XE	X
XE	XEXE RED EYED FEMALE	XEX RED EYED FEMALE
Y	XEY RED EYED MALE	XY WHITE EYED MALE