Pages 266-271, 274

Question 1

Sutton and Boveri

Answer 1

each realized that meiosis could account for Mendel’s rules.

Question 2

Locus

Answer 2

particular position along a chromosome where a gene is located.

Question 3

The physical separation of alleles during anaphase of meiosis I is responsible for

Answer 3

Mendel’s principle of segregation.

Question 4

If the alleles for different genes are located on different chromosomes

Answer 4

they assort independently of one another at meiosis I. this is the physical basis of Mendel’s principle of independent assortment.

Question 5

Chromosome theory of inheritance

Answer 5

states that Mendel’s rule can be explained by the independent alignment and separation of homologous chromosomes at meiosis I.

Question 6

Wild type

Answer 6

most common phenotype for each trait.

Question 7

Mutation

Answer 7

heritable change in a gene.

Question 8

Mutant

Answer 8

individual with a phenotype due to a mutation.

Question 9

X-linked inheritance (X-linkage)

Answer 9

gene residing on the X chromosome.

Question 10

Y-linked inheritance (Y-linkage)

Answer 10

gene residing on the Y chromosome.

Question 11

Sex-linked inheritance (sex-linkage)

Answer 11

general term for inheritance of genes on either sex chromosome.

Question 12

When reciprocal crosses give different results,

Answer 12

it is likely that the gene is located on a sex chromosome – it is sex-linked.

Question 13

Autosomal inheritance

Answer 13

genes on non-sex chromosomes.

Question 14

The discovery of X-linked inheritance convinced most biologists that

Answer 14

the chromosome theory of inheritance of correct.

Question 15

linkage

Answer 15

the tendency of particular alleles of different genes to be inherited together. Seen when genes are on the same chromosome.

Question 16

recombinant

Answer 16

combination of alleles on the X chromosome is different from the combinations of alleles present in the mother.

Question 17

To explain the recombinant phenotypes, Morgan proposed that

Answer 17

gametes with new combinations of alleles were generated when crossing over occurred during prophase of meiosis I in the females.

Question 18

The percentage of recombinant offspring that occur in crosses can be used

Answer 18

to estimate the relative distance between genes.

Question 19

The farther genes are apart on the same chromosome

Answer 19

the more likely it is that a crossover will occur someplace between these genes.

Question 20

genetic map

Answer 20

diagram showing the relative positions of genes along a particular chromosome. Can be created from data on the frequency of crossing over between many genes on the same chromosome.

Question 21

Linked genes are inherited together unless

Answer 21

crossing over occurs between them. When crossing over takes place, genetic recombination occurs.

Question 22

Crossing over is rare between

Answer 22

genes that are close together.

Question 23

Calculate the recombinant frequency

Answer 23

as the number of offspring with recombinant phenotypes divided by the total number of offspring.

Question 24

Sturtevant

Answer 24

proposed that the physical distance between genes determines how frequently crossing over occurs between them.

Question 25

1 centiMorgan (cM)

Answer 25

physical distance that produces 1 percent recombinant offspring.