Genetics Exam 2

Front 1

WZ/ZZ

Back 1

Females are the heterogametic sex

Front 2

What is the easiest way to determine if a particular trait of an organims is autosomally inherited or is sex linked?

Back 2

perform a reciprocal cross

Front 3

How is sex determined in Drosophila

Back 3

by the ratio of X chromosomes to the number of sets of autosomes

Front 4

why do genetic mapping experiments become less accurate when the distances between genes become large?

Back 4

multiple crossovers are more common

Front 5

Trans linkage

Back 5

Repulsed Ab/aB

Front 6

Assume that, regarding a particular gene, one scored 80 second division ascospore arrangement (2:2:2:2 or 2:4:2) and 120 first division arrangements (4:4) in Neurospora. What would be the map distance between he gene and centromere?

Back 6

observed/total=20

Front 7

cytoplasmic inheritance

Back 7

...

Front 8

The number of Barr bodies in a mouse somatic cell is

Back 8

one less than the number of X chromosomes in that cell

Front 9

A plan of genotype C d/C d is crossed to c D/c D and an F1 testcrossed to c d/c d. If the genes are linked and 40 map units apart, the percentage of c d/c d offspring will be

Back 9

20%

Front 10

The Drosophila genes for white eyes (w), tan body 9t0 and vestigial wings (vg) lie at map positions 2, 12, and 42 respectively. The distance, between w and t is 10, t and vg is 30 and w and vg is 40. Out of 1000 progeny, 24 exhibited doube crossovers. What is the degree of interference?

Back 10

0.20

Front 11

A human with Turner's syndrome would represent

Back 11

a monosomic condition 2n-1

Front 12

Two practical benefits of polyploidy that have been exploited by breeders are

Back 12

the associated bigger cell size and sterility

Front 13

Triploids

Back 13

...

Front 14

Consider a species with a diploid (2N) number of 40 chromosomes. How many chromosomes would be found in a monoploid body cell?

Back 14

20

Front 15

If an individual is heterozygous for a reciprocal translocation, we would expect about a

Back 15

50% reduction in fertility

Front 16

Duplication of short segments of DNA are often found in the genomes of organims. These events can be beneficial because

Back 16

the creation of gene families through duplications always have a negative effect on phenotypes

Front 17

XXY mouse

Back 17

male

Front 18

XXY Drosophelia

Back 18

female

Front 19

XO mouse

Back 19

female

Front 20

XO drosophelia

Back 20

Male

Front 21

Autosomal recessive

Back 21

...

Front 22

Autosomal dominant

Back 22

......

Front 23

X-linked recessive

Back 23

.....

Front 24

X-linked dominant

Back 24

...

Front 25

Y linked

Back 25

...

Front 26

Aneuploids

Back 26

organisms with surpluses or deficits of individual chromosomes

Trisomic

Monosomic

Tetra sonic

Nullsomic

Front 27

The map of a chromosome interval is X 5 Y 10 Z. From the cross Xyz/xYZ x xyz/xyz, how many double crossovers would be expected out of 1000 progeny

Back 27

5

Front 28

Maternal effect

Back 28

Nuclear gene products are stored in the egg and then transmitted to offsprings

Front 29

dosage competition

Back 29

...

Front 30

Tortoise-shell cats have a patchwork coloration pattern of orange and black spots. This pattern results from

Back 30

dosage compensation through X inactivation

Front 31

In the tetrad analysis, second division segregation patterns (2:4:2 or 2:2:2:2) result from

Back 31

single crossovers between a gene and centromere

Front 32

You observe the progeny of a Drosophelia cross to consist of all red eyed females and white eyed males. What do you infer about the parental phenotypes

Back 32

while eyes females and red eyed males

Front 33

Diploidy

Back 33

...

Front 34

euploidy

Back 34

...

Front 35

monosomic

Back 35

...

Front 36

Reciprocal translocation

Back 36

a transfer of genetic material between non-homologous chromosomes

Front 37

Because of a translocation involving non-homologous chromosomes, a growth gene suddenly finds itself expressed at a much higher rate and the cell becomes cancerous, this activation of the growth gene is because of

Back 37

position effects

Front 38

In a reciprocal translocation heterozygote, what is the pattern of homologous chromosome association during synapsis

Back 38

a cross shaped configuration of 4 chromosomes is formed

Front 39

In humans, XXY individuals are males with klinefelters syndrome. Which could not give rise to a Klienfelter male

Back 39

nondisjunction in meiosis II in the father

Front 40

Why are triploid species rate?

Back 40

chromosomes in a triploid cannot segregate equally during meiosis causing sterility

Front 41

with nondisjunction, which parent leads to the sex chromosome aneuploid XYY

Back 41

father

Front 42

A husband and wife have normal vision, although both of their fathers are red-green color blind, which is inherited as an X-linked recessive condition. What is the probablility that their first child will be normal vision and male?

Back 42

0.25

Front 43

In a testcross experiments, the frequency of recombination between genes a and d is 0.3; between d and c, 0.2; between c and b, 0.1; between a and c 0/5; and between b and d, 0.3 What is the order of the three genes?

Back 43

a-d-c-b

Front 44

How does the Y chromosome determine maleness in humans

Back 44

by containing a gene coding for the TDF, a protein that directs the development of fetal gonads

Front 45

Cis linkage

Back 45

Coupled: AB/ab

Front 46

Polyploidy

Back 46

In which more than two haploid sets of chromosomes are present, is prevalent in plants and rare in animals

Front 47

Autopolyploidy

Back 47

The addition of one or more sets of chromosomes identical to the haploid complement of the same species

Non junction of entire genome in meiosis

Somatic non disjunction of entire genome followed by reproduction

Colchicine

Even numbers=fertile

Front 48

Allopolyploidy

Back 48

The combination of chromosome sets from different species as a consequence of inter specific matings

Front 49

Reciprocal translocation

Back 49

Involves the exchange of segments between two non homologous chromosomes

Front 50

Absolute linkage

Back 50

.

Front 51

Linkage with recombination

Back 51

.

Front 52

Independent assortmenr

Back 52

..

Front 53

Translocation

Back 53

Movement of chromosomal segment to a new location in the genome.

Down syndrome

Fragile X

Front 54

Robersonian translocation

Back 54

Produces a new, large submetacentric or meta centric chromosomes

Front 55

Trisomic

Back 55

2N+1

Klienfelters

Down syndrome

Jimson weed: different phenotypes

Front 56

Monosomic

Back 56

2N-1

Turner syndrome

Front 57

Tetrasomic

Back 57

2N+2

Front 58

Nullisimic

Back 58

2N-2

Front 59

A haploid cell of a grasshopper

Back 59

has half the amount of the genetic information as a diploid cell of a grasshopper

Front 60

The number of genetically distinct gametes that an individual can produce is predicted

Back 60

using the formula 2^N, where N equals the number of heterozygous gene pairs

Front 61

incomplete dominance

Back 61

the hybrid shows a new phenotype that is intermediate between the two homozygotes

Front 62

co-dominance

Back 62

both phenotypes are equally expressed in hybrids

Front 63

pleiotropy

Back 63

when more than one phenotype results from a single gene

Front 64

complemation test

Back 64

.

Front 65

Genetic ratio of a monohybrid cross (without lethal alleles) in the F2

Back 65

1:2:1

Front 66

Phenotypic ratio of a monohybrid cross with a recessive lethal allele in the F2

Back 66

2:1

Front 67

Phenotypic ratio of a monohybrid testcross

Back 67

1:1

Front 68

Phenotypic ratio of a monohybrid cross with incomplete dominance in the F2

Back 68

1:2:1

Front 69

Phenotypic ratio of a dihybrid cross with dominant epistasis

Back 69

12:3:1

Front 70

Phenotypic ratio of dihybrid cross with recessive epistasis

Back 70

9:3:4

Front 71

Phenotypic ratio of a dihybrid testcross

Back 71

1:1:1:1

Front 72

Phenotypic ratio of a dihybrid cross with double dominant epistasis

Back 72

15:1