Chapter 5

Question 1

incomplete dominance

Answer 1

one allele for specific trait is not completely expressed over its paired allele

Question 2

Complete dominance

Answer 2

dominant allele masks the effect of recessive allele

Question 3

Codominance

Answer 3

The phenotype of the heterozygote is not intermediate between
the phenotypes of the homozygotes; rather it simultaneously
expresses the phenotypes of both homozygotes

Question 4

Levels of phenotype

Answer 4

Anatomical, Physiological, Molecular

Question 5

Pheno Level affects in CF

Answer 5

– Gene responsible is on chromosome 7
– Encodes a protein termed CFTR (
* CFTR -regulates chloride levels and is mutated in CF
* Mutated channel stays closed, chloride ions build up
* In heterozygotes, enough functional CFTR is made to
prevent cystic fibrosis

Question 6

Incomplete penetrance

Answer 6

genotype is not
producing expected phenotype

Question 7

Penetrance

Answer 7

The percentage of individuals
having a particular genotype that express
the expected phenotype

Question 8

Expressivity

Answer 8

the degree to which a trait is
expressed

Question 9

Lethal Alleles

Answer 9

Causes death at an early stage of development, so some
genotypes may not appear among the progeny

Affects the Mendelian
genotypic and phenotypic
ratios in progeny!

Question 10

Multiple alleles:

Answer 10

For a given locus, more than
two alleles are present within a group of
individuals
– The genotype of each individual diploid organisms still only
consists of two alleles!
– Inheritance of characteristics encoded by multiple alleles is no
different than those encoded by two alleles

Question 11

Gene interaction

Answer 11

Effects of genes at one locus depend on the
presence of genes at other loci

Question 12

Sex-linked characteristic

Answer 12

Phenotype Determined by
Sex-linked characteristic Genes located on the sex chromosome

Question 13

Sex-influenced characteristic

Answer 13

Autosomal genes that are more readily expressed in one sex

Question 14

Sex-limited characteristic

Answer 14

Autosomal genes whose expression is
limited to one sex

Question 15

Genetic maternal effect

Answer 15

Nuclear genotype of the maternal parent

Question 16

Cytoplasmic inheritance

Answer 16

Genetic maternal effect Cytoplasmic genes, which are usually
inherited from only one parent

Question 17

Genomic imprinting

Answer 17

Genes whose expression is affected by the
sex of the transmitting parent

Question 18

Epigenetics:

Answer 18

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

Question 19

Genetic Maternal Effect

Answer 19

– phenotype of the
offspring is determined by the genotype of the
mother.

Question 20

Characteristics of cytoplasmically
inherited traits

Answer 20

1. Present in males and females.
2. Usually inherited from one parent, typically the maternal
   parent.
3. Reciprocal crosses give different results.
4. Exhibit extensive phenotypic variation, even within a single
   family

Question 21

Duplicate Recessive Epistasis –

Answer 21

Two recessive alleles at
either of two different loci are capable of suppressing a
phenotype

Question 22

Dominant Epistasis

Answer 22

Only a single copy of an allele is required to inhibit
the expression of an allele at a different locus.

Question 23

Recessive epistasis:

Answer 23

‒ Presence of two recessive alleles inhibits the expression of an
allele at a different locus.
‒ Labrador retriever coat color is determined by interactions
between genes at two loci
‒ One locus determines pigment produced by skin cells
‒ Second locus affects the deposition of the pigment into the shaft
of the hair.

Question 24

epistatic gene.

Answer 24

The gene that does the masking

Question 25

hypostatic gene.

Answer 25

The gene whose effect is masked