Mendel inheritance Flashcards Preview

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Flashcards in Mendel inheritance Deck (29)
1

genetic character

heritable feature such as flower color that varies among individuals

2

genetic trait

variant for a character such as purple or white flower color

3

mendel hybridization

crossing of two true breeding varieties of traits

4

True breeding generations

P generation is parental generation; F1 generation is first generation which is hybrid

5

character inheritance

an organism inherits two alleles; one from each parent

6

law of segregation

two alleles for a heritable character separate during gamete formation and end up in different gametes

7

testcross

breeding of a recessive homozygote with a dominant phenotype but unknown genotype

8

monohybrids

heterozygous for one character

9

dihybrid

heterozygous for two characters

10

dihybrid cross

a cross between F1 hybrids to determine assortment

11

law of independent assortment

each pair of alleles segregate independently of other pairs of alleles during gamete formation

12

complete dominance

F1 plants always looked like one of the two parental varieties of one allele over another

13

codominance

two alleles both affect the phenotype in separate distinguishable ways

14

incomplete dominance

alleles for some characters fall in the middle of the spectrum of dominance

15

blood transfusion

if a type A person receives blood from a type B or type AB donor, the recipients immune system recognizes the foreign B substance and attacks them

16

peiotropy

most genes have multiple phenotypic character effects

17

epistasis

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

18

polygenic inheritance

additive effect of two or more genes on a single phenotypic character; skin pigmentation in humans is controlled by at least 3 separately inherited genes

19

segragation stage

alleles segregate from each other during anaphase I of meiosis

20

linked genes

genes located on the same chromosome that tend to be inherited together in genetic crosses

21

recombinants

offspring have new combinations of traits that produce a different phenotype from the parent

22

genetic map

ordered list of genetic loci along a particular chromosome

23

centimorgans

originally map units; distance between genes; one map unit equals 1% recombination frequency

24

cytogenetic maps

locate genes on chromosomoes by comparing features such as stained bands

25

X chromosome mosaicism

some cells have active X from the father and others have active X from the mother

26

Barr body

the inactive X in each cell of a female condenses into a compact object

27

tortoiseshell cat

only females can have this fur coloration because of the X inactivation

28

nondisjunction

members of a pair of homologous chromosomes do not move apart properly during meiosis I or sister chromatids fail to separate during meiosis II

29

aneuploidy

an aberrant gamete unites with a normal one at fertilization, offspring will have an abnormal number of a particular chromosome