Chapter 7

Question 1

linked genes

Answer 1

Genes located on the same chromosome.

Question 2

linkage group

Answer 2

Genes located together on the same chromosome.

Question 3

nonrecombinant (parental) gamete

Answer 3

Contains only the original combinations of genes present in the parents.

Question 4

nonrecombinant (parental) progeny

Answer 4

Possesses the original combinations of traits possessed by the parents.

Question 5

recombinant gamete

Answer 5

Possesses new combinations of genes.

Question 6

recombinant progeny

Answer 6

Possesses new combinations of traits formed from recombinant gametes.

Question 7

recombination frequency

Answer 7

Proportion of recombinant progeny produced in a cross.

Question 8

genetic map

Answer 8

Map of the relative distances between genetic loci, markers, or other chromosome regions determined by rates of recombination; measured in percent recombination or map units.

Question 9

coupling configuration

Answer 9

See cis configuration.

Question 10

repulsion configuration

Answer 10

See trans configuration.

Question 11

physical map

Answer 11

Map of physical distances between loci, genetic markers, or other chromosome segments; measured in base pairs.

Question 12

map unit

Answer 12

Unit of measure for distances on a genetic map; 1 map unit equals 1% recombination.

Question 13

centiMorgan (cM)

Answer 13

Another name for map unit.

Question 14

two point test cross

Answer 14

Cross between an individual heterozygous at two loci and an individual homozygous for recessive alleles at those loci.

Question 15

three point test cross

Answer 15

Cross between an individual heterozygous at three loci and an individual homozygous for recessive alleles at those loci.

Question 16

interference

Answer 16

Degree to which one crossover interferes with additional crossovers.

Question 17

coefficient of coincidence

Answer 17

Ratio of observed double crossovers to expected double crossovers.

Question 18

mapping function

Answer 18

Relates recombination frequencies to actual physical distances between genes.

Question 19

lod (logarithm of odds score)

Answer 19

Logarithm of the ratio of the probability of obtaining a set of observations, assuming a specified degree of linkage, to the probability of obtaining the same set of observations with independent assortment; used to assess the likelihood of linkage between genes from pedigree data.

Question 20

genetic marker

Answer 20

Any gene or DNA sequence used to identify a location on a genetic or physical map.

Question 21

linkage analysis

Answer 21

Gene mapping based on the detection of physical linkage between genes, as measured by the rate of recombination, in progeny from a cross.

Question 22

genome-wide association studies

Answer 22

Studies that look for nonrandom associations between the presence of a trait and alleles at many different loci scattered across a genome—that is, for associations between traits and particular suites of alleles in a population.

Question 23

haplotype

Answer 23

A specific set of linked genetic variants or alleles on a single chromosome or on part of a chromosome.

Question 24

linkage disequilibrium

Answer 24

Nonrandom association between genetic variants within a haplotype.

Question 25

single nucleotide polymorphism (SNP)

Answer 25

Single-base-pair differences in DNA sequence between individual members of a species.

Question 26

somatic-cell hybridization

Answer 26

Fusion of different cell types.

Question 27

cell line

Answer 27

Genetically identical cells that divide indefinitely and can be cultured in the laboratory.

Question 28

heterokaryon

Answer 28

Cell possessing two nuclei derived from different cells through cell fusion.

Question 29

deletion mapping

Answer 29

Technique for determining the chromsomal location of a gene by studying the association of its phenotype or product with particular chromosome deletions.