Chapter 6

Question 1

The transmission of genes close to one another on the same chromosome violates which of Mendels laws

Answer 1

The law of segregation

Question 2

What is synteny

Answer 2

When two or more genes are located on the same chromosome and are physically linked

Question 3

What is genetic linkage

Answer 3

When genes close together on a chromosome tend to be transmitted as a unit which influences inheritance patterns

Question 4

What causes genes that are far apart to independently assort

Answer 4

Crossing over

Question 5

Linkage is altered during prophase one of meiosis due to crossing over. What do replicated sister chromatids associate as and what do non sister chromatids do

Answer 5

Bivalents
Non sister chromatids exchange dna segments
Crossing over may produce recombinant genotypes

Question 6

In haploid cells what is true regarding linkage

Answer 6

They contain the same combination of alleles as the original chromosomes
The arrangement of linked alleles doesn’t alter in gametes
Without crossing over there can be no recombination

Question 7

What is a non parental or recombinant cell

Answer 7

Haploid cells that contain a combo of alleles not found in the original chromosome

Question 8

How are recombinant offspring produced

Answer 8

The exchange of dna between two homologous chromosomes during meiosis in one or both parents leading to new genetic material

Question 9

According to one of Morgan’s hypothesis why might all three genes be inherited together

Answer 9

They are all on the X chromosome

Question 10

What other major hypothesis did Morgan have

Answer 10

Crossing over results in new combos of alleles
The likelihood of crossing over depends on the distance between the two genes with a higher probability toward genes farther apart

Question 11

What does each gene have

Answer 11

Its own unique locus

Question 12

Why do we do genetic mapping

Answer 12

To determine the linear order of linked genes along the same chromosome

Question 13

What is the map distance equation

Answer 13

Number of recombinant offspring divided by total number of offspring multiplied by 100

Question 14

What is a test cross

Answer 14

An individual that is heterozygous for two or more genes is crossed to one that is homozygous recessive for the same genes

Question 15

What can test cross data be used for

Answer 15

Estimating the distance between two genes
A test cross is expected to yield a maximum of only 50 percent recombinant offspring

Question 16

What can multiple crossovers cause

Answer 16

A limit on measurable recommendation frequencies because the physical distance increases

Question 17

With a combo of traits in a double crossover what can we find out

Answer 17

Which gene is in the middle

Question 18

Why might you have a lower than expected value of crossovers

Answer 18

Positive interference

Question 19

What does a first cross over reduce

Answer 19

The probability that a second crossover will occur nearby

Question 20

What is mitotic recombination

Answer 20

When crossing over occurs during mitosis which leads to a new combo of alleles

Question 21

What might happen during mitotic recombination in early embryonic development

Answer 21

The daughter cells containing the recombinant chromosomes continue to divide and a patch of tissue with different characteristics results