Chapter 5

Question 1

Why don’t linked genes assort independently?

Answer 1

linked genes don’t assort independently because they’re are located close together on the same chromosome making crossing over less likely to occur

Question 2

How can linkage be used to find human alleles that are associated with the disease?

Answer 2

Linkage can be used by studying and identifying specific alleles associated with infected individuals as the disease alleles were not previously sorted independently

Question 3

complete dominance

Answer 3

type of dominance in which the same phenotype is expressed in homozygous (AA) and in heterozygotes (Aa); only dominant allele is expressed in heterozygote

Question 4

incomplete dominance

Answer 4

type of dominance in which the phenotype of the heterozygote is intermediate between the phenotypes of the two homozygotes

Question 5

codominance

Answer 5

type of allele interaction in which heterozygote simultaneously expresses traits of both homozygotes

Question 6

recessive lethal alleles

Answer 6

can code for either dominant or recessive traits, lethal alleles are alleles that can cause the death of the organism that carries them

Question 7

multiple alleles - ABO blood group example

Answer 7

Presence of more than two alleles at a locus in a group of diploid individuals; however, each individual member of the group has only two of the possible alleles

Question 8

gene interaction

Answer 8

interaction between genes at a different loci that affect the same characteristic

Question 9

expressivity

Answer 9

degree to which trait is expressed

Question 10

penetrance

Answer 10

percentage of individuals with a particular genotype that expresses the phenotype expected of the genotype

Question 11

epistasis

Answer 11

type of gene interaction in which a gene of one locus makes or suppresses the effects of a gene at a different locus

Question 12

cytoplasmic inheritance

Answer 12

Inheritance of a characteristic encoded by genes located in the cytoplasm.

most cytoplasmically inherited characteristics are contributed entirely from one parent

Question 13

epigentics

Answer 13

phenomena due to alterations in DNA that do not include changes in the base sequence; often affects the way in which DNA sequences are expressed.

Alterations are often stable and heritable in the sense that they are passed to descendent cells or individuals

Question 14

linked genes

Answer 14

genes close together on the same chromosome