Genetics Lab Exam

Front 1

Is the following statement true or false?
"All the sperm from one human male are genetically identical."

Back 1

False, they're not identical because in meiosis we have "crossing over", which mixes genetic material.

Front 2

Mitosis and meiosis always differ in regards to the presence of, what?

Back 2

Bivalents.

Front 3

Consider a diploid organism that has three pairs of chromosomes. Assume that the organism receives chromosomes A, B, and C from the female parent and A', B' and C' from the male parent. TO answer the following questions, assume that no crossing over occurs.

A) What proportion of gametes of this organism would be expected to contain all the chromosomes of maternal origin?

B) What proportion of the gametes would be expected to contain some chromosomes from both maternal and paternal origin?

Back 3

A) (1/2)^3 = 8

B) [1 - (1/8 + 1/8)] = 6/8 = 3/4

Front 4

How many chromosomes are there in the somatic cells of a newborn baby with:

A) Cri-du chat syndrome
B) Klinefelter syndrome
C) Down syndrome due to a 14/21 Robertsonian translocation
D) Triploidy
E) Edward's Syndrome

Back 4

A) 46, because it's on a deletion of a small section of a chromosome.
B) 47-50
C) 46
D) 69
E) 47

Front 5

A species has a diploid number of 2n. Meiosis I fails during spermatogenesis, the cytoplasm does not divide and only on daughter cell is produced. The resulting sperm fertilizes a normal ovum. What is the chromosomal complement of the embryo? Justify your answer.

Back 5

http://imgur.com/a/IjAag
(Answer in album)

Front 6

The broad bean, Vicia faba, has a haploid number of 6. How many chromosomes would you find in an abnormal triploid cell?

Back 6

2n = 12
3n = 18

Front 7

There are 40 chromosomes in somatic cells of the house mouse.
A) how many chromosomes does a mouse receive from its father?
B) how many autosomes are present in a mouse gamete?
C) how many sex chromosomes are in a mouse ovum?
D) how many autosomes are in somatic cells of a female?

Back 7

2n = 40

A) 20
B) 19
C) 1
D) 38

Front 8

How many chromosomes of humans (2n = 46) will be found in:

A) secondary spermatocyte
B) spermatid
C) spermatozoan
D) spermatogonium
E) primary spermatocyte

Back 8

2n = 46

A) n = 23
B) n = 23
C) n = 23
D) 2n = 46
E) 2n = 46

Front 9

(larger image: http://i.imgur.com/4a1IZUK.png )

The photograph accompanying this question shows the chromosomes from a human cell. Construct and idiogram.

A) is the specimen male or female?
B) what possible kinds of chromosomal abnormalities may be present in this patient

Back 9

(larger image: http://i.imgur.com/djSFJcm.jpg )

A) male
B) trisomy 21

Front 10

The horse has a diploid set of 64 chromosomes, and a donkey has a diploid set of 62 chromosomes. Mules (viable but usually sterile) are produced when a male donkey is bred with a female horse.

A) how many chromosomes will a mule contain?
B) why are mules usually sterile (incapable of producing viable gametes)?

Back 10

Horse = 2n = 64 chromosomes
Donkey = 2n = 62 chromosomes

A) 32 + 31 = 63 chromosomes in a mule
B) 63 chromosomes can't be divided by 2, so there is an impairable number of chromosomes necessary for producing viable gametes

Front 11

A biologist examines a series of cells and counts 160 cells in interphase, 2 cells in metaphase, 7 cells in anaphase, and 5 cells in telophase. If the complete cell cycle requires 24 hours, what is the average duration of each stage in hours?

Back 11

http://imgur.com/a/z2fHJ
(Answer in album)

Front 12

The lack of pigmentation, called albinism, in humans is the result of a recessive allele (a) and normal pigmentation is the result of its dominant allele (A). Two normal parents have an albino child. Determine the probability that:
A) the next child is albino
B) the next 2 children are albinos

Back 12

A) a| = aa
Male = Aa
Female = Aa
25%

B) (1/4)^2 = 1/16 = 6.25
*exponent (2) is the number of children

Front 13

In the F2 of his cross of red-flowered x white-flowered Pisum, Mendel obtained 705 plants with red flowers and 224 with white. Is this result consistent with his hypothesis of factor segregation, from which a 3:1 ratio would be predicted?

Back 13

http://i.imgur.com/SWhSyiK.png

Front 14

A woman of blood group AB marries a man of blood group A whose father was group O. What is the probability that:

A) their two children will both be group A?
B) one child will be group B, and the other group O?
C) the first child will be a son of group AB and the second child a son of group B

Back 14

http://i.imgur.com/3iyQU7A.jpg

Front 15

What percentage of families with four children can we expect to have two boys and two girls?

Back 15

http://i.imgur.com/BU1DmdZ.jpg

Front 16

In humans, alkaptonuria is a disorder in which affected persons produce black urine. Alkaptonuria results from an allele (a) that is recessive to the allele for normal metabolism (A). Sarah has normal metabolism, but her brother has alkaptonuria. Sarah's father has alkaptonuria, and her mother has normal metabolism.
A) Give the genotypes of Sarah, her mother, her father, and her brother.
B) if Sarah's parents have another child, what is the probability that this child will have alkaptonuria?
C) the first child will be a son of group AB and the second child a son of group B

Back 16

http://i.imgur.com/1ebjmkB.jpg

Front 17

Cathy wants to undergo maternal serum screening. She is also strongly opposed to abortion. A friend argues that she is inconsistent. Is her friend right.

Back 17

I think yes, but apparently the answer is no? Because the child is not considered 'human' at that point.
F^ck that.

Front 18

Mr. Jim Haley has a twin sister and two older sisters. He fathered a son with cystic fibrosis, a recessive condition. This son is the propositus that brought the family to medical attention. Draw the pedigree corresponding to this family.

Back 18

http://i.imgur.com/07hn2AW.jpg

Front 19

On chromosome 3 of corn there is a dominant gene (A1), which together with the dominant gene (A2) on chromosome 9, produces coloured aleurone. All other genetic combinations produce colourless aleurone. Two pure colourless strains are crossed to produce an all-coloured F1.

A) what were the genotpyes of the parental strains and the F1?
B) what phenotypic proportions are expected among F2?
C) what genotypic ratio exists among the white F2?

Back 19

http://i.imgur.com/JKbayK5.jpg

Front 20

Matings between black rats of identical genotype produced offspring as follows: 14 cream-coloured, 47 black, and 19 albino.

A) what epistatis ratio is approximated by these offspring?
B) what type of epistasis is operative?

Back 20

http://i.imgur.com/Qy8AG1Y.jpg

Front 21

In humans, red-green colour blindness is recessive and X-lined, while albinism is recessive and autosomal. What types of children can be produced as the result of marriages between two homozygous parents, a normal-visioned albino woman and a colour-blind, normal pigmented man?

Let c and c+ be the colour-blind and normal vision alleles, respectively, and let a and a+ be the albino and normal pigmentation alleles, respectively.

Back 21

http://i.imgur.com/7iTksTd.jpg

Front 22

A normal woman whose mother was colour-blind and whose father had hemophilia (X-linked recessive) marries a colour-blind man. They produce a son and a daughter. Ignoring the effect of crossing-over, what is the probability that:

A) the son is the colour-blind but not hemophiliac?
B) the daughter is phenotypically normal?
C) the son is colour-blind and has hemophilia?
D) the son is normal for both traits?
E) the daughter is colour-blind only?

Back 22

http://i.imgur.com/SCCa8m4.jpg

Front 23

If a normal woman whose father has hemophilia (X linked recessive) marries a man with Marfan syndrome (a rare autosomal dominant), what is the chance that:

A) any son will have hemophilia?
B) any son will have Mafran?
C) any son will have both traits?
D) any daughter will have hemophilia?
E) any daughter will have Marfan?
F) any daughter will have both traits?

Back 23

http://i.imgur.com/EtQlPdM.jpg

Front 24

Many studies have suggested a strong genetic predisposition to migraine headaches, but the mode of inheritance is not clear. Scientists examined migraine headaches in several families. What is the most likely mode of inheritance for migraine headaches in the two families shown below? Explain your reasoning.

Back 24

http://i.imgur.com/YbGc09Q.jpg

Front 25

The Flemish breed of rabbits has an average body weight of 3600 grams. The Himalayan breed has a mean of 1875 grams. Matings between these two breeds produce an intermediate F1 with a standard deviation of 162 grams. The variability of the F2 is greater as indicated by a standard deviation of 230 grams.

A) estimate the number of pairs of factors (genes) contributing to mature body weight in rabbit.
B) estimate the average metric contribution of each active allele.

Back 25

http://i.imgur.com/tz9GKKt.jpg

Front 26

The narrow-sense heritability of ear length in Reno rabbits is 0.4. The phenotypic variance (Vp) is 0.8 and the environmental variance (Vᴇ) is 0.2. What is the additive genetic variance (Vᴀ ) for ear length in these rabbits?

Back 26

http://i.imgur.com/kPyozL2.jpg

Front 27

http://i.imgur.com/NJFP1qg.jpg

(Only A was done here. KNOW HOW TO DO THIS!! IT WILL BE ASKED!!)

Back 27

Part 1: http://i.imgur.com/gWKfq5C.jpg

Part 2: http://i.imgur.com/wpSCqcn.jpg

Front 28

http://i.imgur.com/sq72aI4.jpg

The American black population is primarily of African origin, mixed with some more recent Caucasian ancestry. Estimate the proportion of Caucasian ancestry in American Black populations using alleic frequency for red blood cell antigens.

Back 28

http://i.imgur.com/NR59be3.jpg

Front 29

Consider a population under continued selection. Let us assume that the selective disadvantage of A2A2 is 0.2 and calculate the chance in the frequency A2 over several generations if the initial frequency is of A2 is 0.6.

Back 29

http://i.imgur.com/4jO5F5L.jpg