Ch 14 Mendelian Genetics

Question 1

character

Answer 1

a heritable feature that varies among individuals

Question 2

trait

Answer 2

each variant for a character

Question 3

true breeding

Answer 3

plants that produce the same variety as the parent plant over many generations of self-pollination

Question 4

Hybridization

Answer 4

mating/crossing of two true breeding varieties

Question 5

P generation

Answer 5

true breeding parents

Question 6

F1 generation

Answer 6

first filial generation, hybrid offspring of P generation

Question 7

F2 generation

Answer 7

second filial generation, f1 hybrids self pollinate or cross pollinate with other F1 hybrids

Question 8

allele

Answer 8

alternative version of a gene

Question 9

dominant allele

Answer 9

determines the organism’s appearance

Question 10

recessive allele

Answer 10

no noticeable effect on the organism’s appearance

Question 11

law of segregation

Answer 11

two alleles for a heritable character segregate (from each other) during gamete formation and end up in different gametes

Question 12

punnett square

Answer 12

diagrammatic device for predicting the allele composition of offspring

Question 13

homozygote

Answer 13

organism that has a pair of identical alleles for a gene encoding character (organism is homozygous)

Question 14

heterozygote

Answer 14

organism that has two different alleles for a gene (organism is heterozygous)

Question 15

phenotype

Answer 15

an organism’s observable traits

Question 16

genotype

Answer 16

genetic makeup

Question 17

testcross

Answer 17

breeding an organism of unknown genotype with a recessive homozygote, reveals unknown genotype

Question 18

monohybrids

Answer 18

heterozygous for one particular character

Question 19

monohybrid cross

Answer 19

cross between monohybrids

Question 20

dihybrid

Answer 20

heterozygous for two characters

Question 21

dihybrid cross

Answer 21

a cross between F1 dihybrids

Question 22

law of independent assortment

Answer 22

two or more genes assort independently - each pair of alleles segregates independently of any other pair of alleles

Question 23

complete dominance

Answer 23

phenotypes of the heterozygote and dominant homozygote are indistinguishable

Question 24

incomplete dominance

Answer 24

phenotype is somewhere between those of the two parental varieties

Question 25

codominance

Answer 25

two alleles each affect the phenotype in separate, distinguishable ways

Question 26

discrete

Answer 26

Discrete, or discontinuous, traits are controlled by a small number of genes, often only one. These genes generally have two alleles.

Question 27

pleiotropy

Answer 27

having multiple phenotypic effects

Question 28

epistasis

Answer 28

the phenotypic expression of a gene at one locus alters that of a gene at a second locus

Question 29

quantitative characters

Answer 29

vary in the population in gradations along a continuum

Question 30

polygenic inheritance

Answer 30

an additive effect of two or more genes on a single phenotype character

Question 31

multifactorial

Answer 31

many factors, both genetic and environmental, collectively influence phenotype

Question 32

pedigree

Answer 32

family tree showing the occurrence of heritable characters in parents and offspring over multiple generations

Question 33

carriers

Answer 33

heterozygotes that transmit the recessive allele to their offspring