Heredity

Question 1

Heredity

Answer 1

To determine the probablity of two or more independent events occurring together multiply the probabilities of each separate event

Question 2

gene

Answer 2

genetic material on a chromosome for a trait

Question 3

allele

Answer 3

variance of genes such as different color

Question 4

homologous chromosomes

Answer 4

a pair of chromosomes that contains same genetic material (gene for gene). Each parents contributed 1 of the chromosomes in the pair

Question 5

law of segregation

Answer 5

one member of each chromosome pair migrates to an opposite pole so that each gamete is haploid (aka each gamete has only one copy of each allele. Occurs i anaphase 1

Question 6

Law of independent assortment

Answer 6

Independant assortment of alleles. migration of homologues within one pair of homologous chromosomes does not influence the migration of homologues of other homologous pairs

Question 7

What is similar between law of segregation and law of independent assortment?

Answer 7

1) both pertain to meiosis

2) both contribute to genetic variety

Question 8

What is different between law of segregation and law of independent assortment?

Answer 8

The difference is that law of segregation is
basically “when we form gametes we separate our allele copies so gametes are haploid” and law of independent assortment says “the separation of each pair of chromosomes is completely independent from the separation of any other pair -they each separate at random, outcome of one doesn’t affect others”

Question 9

Test crosses

Answer 9

Monohybrid crosses test one gene, Dihybrid test two. Crosses have P, F1, and F2 generations

Question 10

Incomplete Dominance

Answer 10

Blending of expressions of alleles

Ex: pink flower from a red parents and white parent

Question 11

Codominance

Answer 11

both inherited alleles are completely expressed

Ex: Blood

Question 12

Multiple alleles

Answer 12

Blood groups have 3 possible alleles, the codominant A and B and the O, leading to 4 possible genotypes: AO (A type), BO (B type), AB (codominant AB type), OO (O type)

Question 13

phenotype

Answer 13

the set of observable characteristics determined by genotype

Question 14

genotype

Answer 14

the genetic constitution of an individual organism

Question 15

Epistasis

Answer 15

one gene affects phenotypic expression of 2nd gene
Ex: Pigmentation (one gene controls (turn on/off) the production of pigment, and 2nd gene controls color or amount). If 1st gene codes for no pigment => 2nd gene has no effect

Question 16

Pleiotropy

Answer 16

single gene has more than 1 phenotype expression
Ex:gene in pea plants that expressed seed texture also influences phenotype of starch metabolism and water uptake
Ex: sickle cell anemia leads to different health conditions

Question 17

Polygenic inheritance

Answer 17

the interaction of many genes to shape a single phenotype with continuous variation (height, skin, color))

Question 18

Linked genes

Answer 18

two or more genes that reside on the same chromosomes and thus cannot separate independently bc they are physically connected (inherited together)

Question 19

Linkage map

Answer 19

B-V is 18%, A-V is 12%, and B-A is 6% => B——A————V

Question 20

Linked genes exhibit recombination about ____% of the time

Answer 20

18%. This means that is bv and BV are linked, we will see the recombinate Bv or bV 18% of the time

Question 21

Sex linked

Answer 21

refers to when a single gene resides on sex chromosome; when male (XY) receives an X from mother, whether it is dominant or recessive will be expressed because there is no copy on the Y chromosome

Question 22

sex-influenced

Answer 22

an be influenced by sex of individual carrying trait (e.g. Bb female not bald, Bb male is)

Question 23

Penetrance

Answer 23

probability an organism with a specific genotype will express a particular phenotype

Question 24

expressivity

Answer 24

term describing the variation of phenotype for a specific genotype

Question 25

X-inactivation

Answer 25

during embryonic development in female mammals, one of two X chromosomes does not uncoil into chromatin. Barr body is dark and coiled compact body chromosome that is not expressed, making the genes on the other X chromosome expressed. Either one can be inactivated; genes in a female will not be expressed similarly, so all cells in a female mammal not necessarily functionally identical

Question 26

Example of X-inactivity?

Answer 26

calico cats (always female)

Question 27

hemophilia

Answer 27

cannot form blood clot

Question 28

nondisjuncton

Answer 28

failure of one or more chromosome pairs or chromatids to separate during mitosis.

Question 29

When can nondisjuntion happen?

Answer 29

1) Mitosis -failure of two chromatids of a single chromosome during anaphase
2) meiosis -homologous chromosomes to separate during Meiosis I (anaphase 1) or sister chromatids to separate during Meiosis II (anaphase 2); result in trisomy or monosomy; ex Down syndrome

Question 30

What is a resulting disorder when nondisjunction happens?

Answer 30

trisomy or monosomy; ex Down syndrome

Question 31

Mosaicism

Answer 31

in cells that undergo nondisjunction in mitosis during embryonic development; fraction of body cells have extra or missing chromosome

Question 32

Polyploidy

Answer 32

all chromosomes undergo meiotic nondisjunction and produce gametes with twice the number of chromosomes. Common in plants