Ch 11 and 12

Question 1

Mendel’s Model for Inheritance

Answer 1

variation in characteristics are from multiple versions of genes, an offspring inherits one allele from each parent per trait, dominant allele determines phenotype

Question 2

Law of Segregation

Answer 2

each gamete gets only one allele

Question 3

true breeding

Answer 3

homozygous dominant or recessive parents

Question 4

test crossing

Answer 4

hybridization by crossing two true breds

Question 5

monhybrid cross

Answer 5

cross of two heterozygous individuals for one trait

Question 6

dihybrid cross

Answer 6

cross of two heterozygous individuals for two traits

Question 7

law of independent assortment

Answer 7

when crossing two traits, they are entirely independent, creating 16 genotypes instead of still just 4

Question 8

complete dominance

Answer 8

one allele determines the phenotype

Question 9

incomplete dominance

Answer 9

combination of alleles creates an inbetween phenotype (red + white = pink)

Question 10

codominance

Answer 10

combination of alleles creates a mix of phenotype (red + white = spotted colors)

Question 11

epistasis

Answer 11

a double trait relationship in which the second trait alters the state of the first

Question 12

polygenic inheritance

Answer 12

a trait combination that is on a spectrum of phenotypes (skin color)

Question 13

multiple alleles

Answer 13

one trait has more than one possible allele (blood type has three)

Question 14

pleiotropy

Answer 14

a single allele combination that determines multiple characteristics

Question 15

chromosome theory of inheritance

Answer 15

the way we knew how inheritance worked: 1. chromosomes and genes are both paired with diploid. 2. alleles separate during meiosis. 3. fertilization restores pairs

Question 16

Morgan’s experiments: why the fly?

Answer 16

used fruit fly, creates hundreds of offspring in one mating, new generation can occur in two weeks, only 4 chromosomes

Question 17

Morgan’s experiments: sex-linked

Answer 17

discovered flies with red and white eyes and the ratios of males and females, more males had mutation, X-linked traits

Question 18

Sex-determining region of Y (SRY)

Answer 18

a region that must be present to convert ovaries to testes on the Y chromosome

Question 19

X-linked genes

Answer 19

have both sex related and non-sex related traits

Question 20

hemizygous

Answer 20

because Y has no allele, the X has only one allele for males so it cant be homo or hetero, its hemi

Question 21

X inactivation

Answer 21

most of one female X chromosome is inactivated during pregnancy because don’t need double genes

Question 22

linked genes

Answer 22

genes located near each other tend to be inherited together

Question 23

Morgan’s experiment: linked genes

Answer 23

black body and small wings or gray body and normal wings; when parental frequency is more than 1/2 is it linked

Question 24

recombination of linked genes

Answer 24

when offspring have different phenotypes than parents, close genes evidently did cross-over; often creates entirely new genes

Question 25

linkage map

Answer 25

shows distance and recombination frequency on genes

Question 26

Chi-square test

Answer 26

observed and expected frequency value showing that the frequency differences are due to chance OR due to a genetic pattern; based on df and p=0.05

Question 27

nondisjunction

Answer 27

chromosome separation goes wrong; one gamete has two, one has three

Question 28

aneuploidy

Answer 28

monosomic = 2n-1; trisomic = 2n+1

Question 29

polyploidy

Answer 29

created by trisomic aneuploidy on every chromosome so that the organism is 3n

Question 30

chromosomal deletion

Answer 30

fragment of chromosome deleted

Question 31

chromosomal duplication

Answer 31

fragment added to a chromosome as an exact copy

Question 32

chromosomal inversion

Answer 32

reversed segment within a chromosome

Question 33

translocation

Answer 33

moves a chromosome’s section to a nonhomologous chromosome