Unit 4- Extensions and Mods of Basic Principles

Question 1

complete dominance

Answer 1

phenotypes of heterozygotes is same as phenotypes of 1 of the homozygotes
(red or white flowers)

Question 2

incomplete dominance

Answer 2

phenotypes of heterozygotes is intermediate (fall in range) between 2 phenotypes of 2 homozygotes
(pink flowers)

Question 3

codominance

Answer 3

phenotype of heterozygotes has both phenotypes of both homozygotes
(red and white speckled flowers)

Question 4

CFTR

Answer 4

channel in the membrane that regulated chloride levels
- mutated in cystic fibrosis
- mutated channel stays closed, so chloride ions build up
- in heterozygotes, enough functional CFTR is made to prevent cystic fibrosis

Question 5

penetrance

Answer 5

the % of indiv having a particular genotype that express the expected phenotype

Question 6

expressivity

Answer 6

the degree to which a trait is expressed

Question 7

multiple alleles

Answer 7

for a given locus, more than 2 alleles are present w/in a group of indiv

Question 8

gene interaction

Answer 8

effects of genes at 1 locus depend on the presence of genes at other loci
- exhibit indep assortment, but do not act indep in their pheno expression
- the product of genes at diff loci interact to produce new pheno
(red pepper + cream pepper yield red, peach, orange, and yellow peppers)

Question 9

epistasis

Answer 9

one gene masks the effect of another

Question 10

recessive epistasis

Answer 10

9:3:4 F2

Question 11

dominant epistasis

Answer 11

12:3:1 F2

Question 12

duplicate recessive epistasis

Answer 12

9:7 F2

Question 13

duplicate dominant epistasis

Answer 13

15:1 F2

Question 14

complementation

Answer 14

determine whether mutations are at the same locus or at diff loci

Question 15

test

Answer 15

parents homozygous for diff mutations are crossed; offspring are heterozygous

Question 16

allelic

Answer 16

occur at same locus

Question 17

if mutations are allelic:

Answer 17

heterozygous offspring have only mutant alleles. exhibit mutant pheno

Question 18

if mutations occur at diff loci

Answer 18

heterozygous offspring inherit a mutant allele and a wild-type allele. Exhibit wild-type pheno

Question 19

sex-influenced characteristics

Answer 19

pheno determined by autosomal genes that are more readily expressed in one sex (ex: beards in goats)

Question 20

sex-limited characteristics

Answer 20

pheno determined by autosomal genes whose expression is limited to 1 sex
(ex: only sons have precocious puberty)

Question 21

cytoplasmic inheritance

Answer 21

-present in males and females
- typically inherited from mom
- reciprocal crosses = diff results
- exhibit extensive phenotypic variation, even w/in family
(ex: mitochondrial DNA)

Question 22

Genetic maternal effect

Answer 22

pheno affected by nuclear genotype of the maternal parent

Question 23

epigenetics

Answer 23

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

Question 24

genomic imprinting

Answer 24

• type of epigenetics
• differential expression of genetic material depending on whether it is inherited from the male or female parent

Question 25

anticipation

Answer 25

a genetic trait becomes more strongly expressed or is expressed at an earlier stage as it is passed from gen to gen
- due to expansion of unstable region of DNA

Question 26

temp-sensitive allele

Answer 26

an allele whose product is functional only at certain temp

Question 27

discontinuous characteristics

Answer 27

relatively few phenotypes (ex: peas, fur color, etc)

Question 28

continuous characteristics

Answer 28

continuous distribution of pheno; occurs when genes at many loci interact (ex: human height)

Question 29

polygenetic characteristics

Answer 29

characteristics encoded by genes at many loci

Question 30

pleiotropy

Answer 30

1 gene affects multiple characteristics