L2 mendelian genetics and probability

Question 1

dihybrid crosses and ratio

Answer 1

cross between individuals that differ in two loci of interest
9:3:3:1

Question 2

principle of independent assortment

Answer 2

the alleles of different genes segregate or assort, independently of each other (if the alleles are “unlinked” *on different chromosomes or far away enough)

Question 3

mitosis ploidy (start -> end)

Answer 3

begins and ends with same ploidy (2n->2n) *ONE DIVISION

Question 4

meiosis ploidy (start -> end)

Answer 4

ends with half ploidy (2n->n) TWO DIVISIONS

Question 5

metaphase 1

Answer 5

replicated chromosomes are paired and line up to be separated

Question 6

anaphase 1

Answer 6

maternal and paternal chromosomes separate

Question 7

telophase 1

Answer 7

chromosomes and alleles are separated into different cells

Question 8

telophase 2

Answer 8

each allele is recovered in half the products of meiosis

Question 9

what are meiotic errors called? and definition

Answer 9

nondisjunction: chromosomes fail to properly segregate in meiosis

Question 10

when there’s nondisjunction in meiosis 1, what is the ploidy of gametes?

Answer 10

two are n+1 and two are n-1

Question 11

when there’s nondisjunction in meiosis 2, what is the ploidy of gametes?

Answer 11

two are n, one is n+1 and one is n-1

Question 12

when finding probability of something and something else, what rule?

Answer 12

product rule: multiply

Question 13

when finding probability of something or something else, what rule?

Answer 13

sum rule: add

Question 14

what two things signify that you can hypothesize that a trait is controlled by a single gene?

Answer 14

having F1 gen be all the same and the ratio of F2 is around 3:1

Question 15

what is the chi squared test for? lots of things

Answer 15

it evaluates whether the predictions of a genetic hypothesis agree with data from the experiment

a goodness of fit test

used to determine if deviations in the data are caused by chance or a “real” difference

Question 16

when do we accept or reject our hypothesis? (chi squared)

Answer 16

we reject if the test statistic is more than 5% critical value

Question 17

how do we look at a pedigree and tell if a trait is dominant?

Answer 17

if a dominant trait is associated with reduced viability or fertility, most people who show the trait are heterozygous, and half their children should inherit the condition

Every person w the trait has at least one dominant allele

every affected individual has at least one affected parent

Question 18

how do we look at a pedigree and tell if a trait is recessive?

Answer 18

rare recessive traits are most likely to appear in a pedigree when spouses are RELATED to each other

recessive traits may occur in individual whose parents are not affected

recessive traits are rare