LECTURE 3 - STUDY GUIDE

Question 1

Regarding non-Mendelian genetics, which statement accurately describes continuous variation?

Answer 1

• The greater the number of genes that influence a character

Question 2

Regarding non-Mendelian genetics, which statement describes an example of continuous variation discussed in class?

Answer 2

Examples: 8 foot tall people

Question 3

Regarding non-Mendelian genetics, which statement accurately describes pleiotropic effects?

Answer 3

An individual allele has more than one effect on the phenotype

Question 4

Regarding non-Mendelian genetics, which statement describes an example of pleiotropic effects discussed in class?

Answer 4

Effects from diseases such as sickle-cell anemia and cystic fibrosis

Question 5

Regarding non-Mendelian genetics, which statement accurately describes incomplete dominance?

Answer 5

Not all alternative alleles are fully dominant or fully recessive in heterozygotes:

Question 6

The coat color in mice is incompletely dominant. Yellow and white-colored mice are homozygous, while cream-colored mice are heterozygous. If two cream-colored mice mate, what phenotypic ratio can we expect of their offspring?

Answer 6

3:1

Question 7

In radishes, red and white are pure-breeding colors, while hybrids are purple. If a red radish is crossed with a white radish, what will be the phenotype of the F2 generation (assuming the F1generation self-pollinates)?

Answer 7

there will be 1 red radish (RR), 2 purple radishes (Rr), and 1 white radish (rr)

Question 8

Regarding non-Mendelian genetics, which statement describes an example of incomplete dominance discussed in class?

Answer 8

Example: You can have a red flower, a pink flower or white it not just one or the other

Question 9

Regarding non-Mendelian genetics, which statement accurately describes environmental effects affecting genetic expression?

Answer 9

The degree to which an allele is expressed may depend on the environment

Question 10

Regarding non-Mendelian genetics, which statement describes an example of environmental effects affecting genetic expression discussed in class?

Answer 10

Arctic fox

Question 11

Regarding non-Mendelian genetics, which statement accurately describes epistasis?

Answer 11

One gene interferes with the expression of another gene

Question 12

Regarding non-Mendelian genetics, which statement describes an example of epistasis discussed in class?

Answer 12

The white and purple corn example in which both genes (that are dominant genes) must be expressed in order to express the gene itself

Question 13

Carl Correns (1900) and Walter Sutton (1902) were two scientists who contributed to the discovery of the chromosomal theory of inheritance. Which statement describes this theory?

Answer 13

The first Principle:

diploid/somatic cells are going to have two copies

gametes/sex cells will always have 1 copy of chromosomes

Question 14

Carl Correns’s (1900) and Walter Sutton’s (1902) work led to the chromosomal theory of inheritance. Which of these statements describe this theory?

Answer 14

The second Principle: chromosomes are going to segregate during meiosis specifically in
meta/anaphase. Won’t be the same as parent because of crossing over and synapsis in
prophase.

Question 15

46. Which statement does not describe the results of Thomas Hunt Morgan’s sex-linked experiments (know information pertaining to the 𝐹1 and 𝐹2 generations)?

Answer 15

𝐹_1 results 100% red eyes

𝐹_2 results 25% red eye male (50% if male)

Question 16

A trait determined by a gene on the X chromosome is said to be _______________ because the behavior of the trait in crosses correlates with the sex of the individual. Fill in the blank.

Answer 16

sex linked or x linked

Question 17

A recessive X-linked trait is always expressed in males (since they only have one X sex chromosome) if they inherit a recessive X-linked trait from their mother. We know then it is genetically more likely for a male to inherit a sex-linked recessive trait. However, how is it possible (what must be the genetics of the parents) for a female to inherit a recessive X-linked trait?

Answer 17

Yes if the mother is a carrier and the father has to have (recessive) white eyes.

Mom: XrXr or XRXr

Dad: XrY

Offspring: XrXr

Question 18

Color blindness is a recessive, sex-linked (X-linked) disorder in humans. A colorblind man has a child with a woman who is a carrier of the disorder. What is the chance that the offspring will be colorblind?

Answer 18

50%

Question 19

In Guinea pigs, the genotype (BB) is black, and the genotype (bb) is white color, and (Bb) is grey color, The gene (B) and (b) are sex-linked. What type of offspring are to be expected in a cross between a grey female and a black male?

Answer 19

Black→50%

Grey→50%

Question 20

Hemophilia is also a sex-linked trait. A normal man marries a normal woman and they have a child with hemophilia. What are the genotypes of the parents?

Answer 20

XRXr and XRY

Question 21

In fruit flies, white eyes is a sex-linked recessive trait. Normal eye color is red. If a white-eyed male is crossed with a heterozygous female, what is the proportion of the offspring will have red eyes?

Answer 21

50%