Week 1

Question 1

what are the 2 types of genetic selection

Answer 1

natural or artificial

Question 2

define: domestication

Answer 2

purposeful mating of individuals with desirable phenotypes for greater expression of those characteristics in offspring

Question 3

when did dogs first occur

Answer 3

~15,000 years ago

Question 4

when did the domestication of pigs, goats, sheep, and cattle occur

Answer 4

~10,000 years ago

Question 5

how are dogs and wolves related

Answer 5

they have the same genes

Question 6

what species did Dmitry Belyaev perform experiments on

Answer 6

silver foxes

Question 7

how are silver foxes and red foxes related

Answer 7

silver foxes are a recessive phenotype

Question 8

what did Belyaev prove in terms of the behaviour of silver foxes

Answer 8

their behaviour remained intact even when they were raised by mothers of the opposite breed

Question 9

when were crops domesticated and where

Answer 9

• ~13,000 years ago
• in the Middle East

Question 10

what are true-breeding lines

Answer 10

breeds where offspring carry parental traits that remain constant from one generation to the next

Question 11

what plant did Mendelian use to study genetics

Answer 11

garden peas

Question 12

define: phenotype

Answer 12

observable characteristic (commonly referred to as a trait)

Question 13

define: genotype

Answer 13

genetic make-up, description of the genetic information carried by an individual

Question 14

how is self-fertilization prevented when performing cross-fertilization

Answer 14

the anthers (producer of pollen/male gametes) is removed

Question 15

what does reciprocal cross-fertilization mean

Answer 15

2 organisms of different genotypes are mated in 2 ways
1. Male (Parent A) x Female (Parent B)
2. Male (Parent B) x Female (Parent A)

Question 16

is each seed of a garden pea genetically identical

Answer 16

no, each seed can have a different genotype

Question 17

what is a true-breeding line

Answer 17

the offspring always show the same phenotype as the parent plants

Question 18

define: monohybrid cross

Answer 18

the mating of true-breeding parents with antagonistic traits (only 1 differing trait) [Ww]

Question 19

define: P generation

Answer 19

parental: it is the first generation in the breeding experiment

Question 20

define: F1 generation

Answer 20

first filial: first offspring of the P generation

Question 21

define: F2 generation

Answer 21

second filial: derived from the interbreedings of F1

Question 22

is it possible for the a lost trait (e.g. breeding tall and dwarf plants resulting only in tall plants) to reappear

Answer 22

yes

Question 23

define: alleles

Answer 23

alternative forms of a single gene

Question 24

what are discrete units of inheritance

Answer 24

alleles

Question 25

define: homologous chromosomes

Answer 25

chromosomes with the exact same genes that have different alleles

Question 26

how are genes/alleles notated

Answer 26

with italics

Question 27

what genotype does *WW* represent

Answer 27

homozygous dominant

Question 28

what genotype does *Ww* represent

Answer 28

heterozygous

Question 29

what genotypes does *ww* represent

Answer 29

homozygous recessive

Question 30

define: polymorphic gene

Answer 30

gene with several alleles that normally occur in a population

Question 31

define: monomorphic gene

Answer 31

gene that has only one allele normally present in a population (however other alleles can exist!)

Question 32

how many alleles for one gene can exist in a diploid individual

Answer 32

a maximum of two

Question 33

what is the law of segregation

Answer 33

two alleles for each trait separate during gamete formation, then unite **at random**, one from each parent, at fertilization

Question 34

what is the phenotypic ratio for a heterozygous cross [*Ww* x *Ww*]

Answer 34

3:1

Question 35

what is the genotypic ratio for a heterozygous cross [*Ww* x *Ww*]

Answer 35

1:2:1

Question 36

what does it mean to be a dominant/recessive trait at the DNA level

Answer 36

no conclusions can be made

Question 37

which gene is there a mutation for in wrinkled peas

Answer 37

SBE1, starch-branching enzyme 1 SBE1 in inactive due to the mutation

Question 38

what does the inactivity of SBE1 lead to

Answer 38

starch doesn't branch, leading to an excess of water in young peas, and the loss of water once they mature

Question 39

what genotype do you use when conducting test crosses

Answer 39

homozygous recessive

Question 40

what is another way of conducting test crosses for some organisms

Answer 40

self-fertilizing

Question 41

what is the law of product

Answer 41

the probability of two or more independent events occurring together is the product of the probabilities that each event will occur itself [probability of *aa* from a cross of *Aa* and *Aa* is 1/2 x 1/2 = 1/4]

Question 42

what is the law of sum

Answer 42

the probability of either of two mutually exclusive events occurring is the sum of their individual probabilities [probability of producing a yellow pea (dominant) from a cross between heterozygous plants is (1/2 x 1/2 )|*GG*| + (1/2 x 1/2)|*Gg*| + (1/2 x 1/2) |*gG*|]

Question 43

define: dihybrid cross

Answer 43

mating between individuals that differ in two traits, where alleles of 2 genes act independently in a dominant and recessive manner [*GgWw*]

Question 44

is it possible for new phenotypic combinations to appear from a monohybrid cross

Answer 44

traits may reappear, but no new ones appear

Question 45

is it possible for new phenotypic combinations to appear from a dihybrid cross

Answer 45

yes

Question 46

how do the law of segregation and the law of independent assortment differ

Answer 46

law of segregation - how different **alleles** of a gene behave law of independent assortment - how different **genes** behave

Question 47

what is mendel's law of independent assortment

Answer 47

during gamete formation, different pairs of alleles segregate independently of each other

Question 48

know how to draw a branching diagram [e.g. *GgWw* x *GgWw*]

Answer 48

should end up with: 1/16 *GGWW* 2/16 *GGWw* 1/16 *GGww* 2/16 *GgWW* 4/16 *GgWw* 2/16 *Ggww* 1/16 *ggWW* 2/16 *ggWw* 1/16 *ggww*

Question 49

what are the phenotypic rations for a *GgWw* x *GgWw* cross [yellow/green, round/wrinkled]

Answer 49

9/16 *G_W_* 3/16 *G_ww* 3/16 *ggW_* 1/16 *ggww*

Question 50

how many test cross possibilities are there to find the genotype of a yellow, round pea

Answer 50

4

Question 51

define: multihybrid

Answer 51

matings between individuals that differ in three or more traits [e.g. *AaBbCcDd*]

Question 52

what is the probability of an *AAbbCcDd* offspring from a *AaBbCcDd* x *AaBbCcDd* cross (use the law of product and genotypic ratios!)

Answer 52

1/4 x 1/4 x 1/2 x 1/2 = 1/64

Question 53

which law allows you to treat alleles of a single gene independently

Answer 53

law of segregation

Question 54

which law allows you to treat different genes separately

Answer 54

law of independent assortment

Question 55

what is the probability of an *aaBbCcDd* offspring from a *aaBbCCDd* x *AaBbccDD* cross

Answer 55

1/2 x 1/2 x 1 x 1/2 = 1/8

Question 56

define: continuous trait

Answer 56

trait with many intermediate forms [e.g. skin colour]

Question 57

define: discrete trait

Answer 57

trait with no intermediate forms [e.g. yellow or green peas]

Question 58

define: parental type

Answer 58

F₂ progeny that look like one of the parents

Question 59

define: recombinant type

Answer 59

F₂ progeny with new phenotypic combinations