mendelian genetics

Question 1

garden pea study what is it/ why peas

Answer 1

mendel chose garden peas to study genetic inheritance
pea plants inherit flower color
garden peas have both male and female sex organs and can cross pollinate and self-pollinate

Question 2

inheritance

Answer 2

how genetic info is passed from parents to offspring
generation to generation

Question 3

character

Answer 3

a heritable feature that varies among individuals

Question 4

trait
trait in pea study

Answer 4

each variant for a character
in this case the trait was either a purple or white colored flower

Question 5

mendel’s experiment broken down in generations

Answer 5

p(parent) generation : true breeding parents produce offspring of the same variety over many generations of self pollination —> he fertilized true breeding plants of one trait with true breeding plants of another trait (purple and white flowers)
F1 generation: mono hybrid offspring = all 1 trait which was purple
F2 generation: F1 self-fertilize and recessive trait reappeared (white)

Question 6

hybridization

Answer 6

crossing of true-breeding variants
parent generation of true breeding variants

Question 7

conclusions from mendel’s experiment

Answer 7

every individual has 2 genes for a character, and genes have 2 variant forms called alleles

alleles may exist in 2 forms, dominant or recessive

there is a 3:1 ratio between traits in F2 generation

Question 8

law of segregation and how alleles are separated and recombined

Answer 8

two alleles of a gene separate from each other during gamete formation, so that each sperm and egg end up with only one allele

alleles separate into different haploid cells that eventually give rise to gametes (segregation during meiosis), so that every gamete only receives one allele

during fertilization, male and female gametes randomly combine with each other

Question 9

genotype

Answer 9

genetic composition on an individual
PP = homozygous dominant
Pp = heterozygous
pp = homozygous recessive

Question 10

phenotype

Answer 10

physical or behavioral characteristics as a result of gene expression

PP = purple flowers
Pp = purple
pp = white flowers

Question 11

mono hybrid cross

Answer 11

cross between heterozygotes

Question 12

punnet square results for mono hybrid cross

Answer 12

3 genotypes PP Pp pp
2 phenotypes 3:1 ratio

Question 13

two factor cross

Answer 13

observing 2 characters at a time
follows inheritance of two characters

YYRR x yyrr
on punnet square = YR YR. x yr yr

Question 14

in f1 generation, what do you see after doing a two factor cross

Answer 14

dihybrid

offspring are hybrids with respect to each trait YyRr

Question 15

in f2 generation what were the two hypothesis proposed for how this generation would look

Answer 15

dependent assortment leading to 3:1 phenotypic ratio

independent assortment leading to 9:3:3:1 phenotypic ratio

Question 16

what was observed in the f2 generation two factor cross

Answer 16

9:3:3:1 phenotypic ratio

Question 17

law of independent assortment

Answer 17

alleles of different genes assort independently of each other during the process that gives rise to gametes : meiosis

Question 18

law of segregation

Answer 18

two alleles of a gene separate from one another during meiosis so every gamete receives only one allele

Question 19

multiplication rule of probability

Answer 19

probability that 2 or more independent events will occur is equal to the product of their individual probabilities

ex: getting one outcome one time and getting the same outcome another time

Question 20

addition rule rule of probability

Answer 20

probability that 2 or more mutually exclusive events will occur

getting one outcome one time or getting another outcome

Question 21

complete dominance

Answer 21

one allele is dominant over another
PP and Pp give rise to same phenotype

Question 22

non-mendelian genetics

Answer 22

when inheritance of characters deviates from simple mendelian genetics through the following situations
1. incomplete dominance/codominance of alleles
2. multiple alleles
3. pleiotropy

Question 23

when certain alleles are not completely dominant or recessive

Answer 23

incomplete dominance or codominance

Question 24

incomplete dominance

Answer 24

neither allele is completely dominant

phenotype of heterozygous individuals is intermediate between the two alleles

purple and white flower —> pink flower

Question 25

incomplete dominance viewed over generations

Answer 25

P generation: red and white flower
F1 : pink
F2 : red, white, and pink are present

Question 26

why does incomplete dominance occur

Answer 26

heterozygous dominant genotype is in between the enzyme activity level of homozygous dominant and homozygous recessive

Question 27

codominance

Answer 27

neither allele is completely dominant but phenotype of heterozygous individuals consists of both the phenotypes of the two alleles

stripes and spots

Question 28

multiple alleles

Answer 28

most genes exist in populations in more than 2 alleles forms
humans have four blood groups (A,B, AB, or O) are determined by 3 alleles

some genes have more than two alleles that control it

Question 29

pleiotropy

Answer 29

most genes have multiple phenotypic effects
responsible for multiple symptoms associated with generation hereditary diseases, such as sickle cell disease
2 copies of sickle cell allele

single gene can sometimes produce multiple phenotypes

Question 30

epistasis

Answer 30

when there are 2 or more genes involved in determining a particular phenotype
when one gene affects the phenotype of another gene because the two gene products interact —> masking of genes

gene at one locus alters that of a gene at a second locus

Question 31

polygenic inheritance

Answer 31

multiple genes independent affect a single trait

Question 32

pedigree traits (general)

Answer 32

square = male
circle = female
filled in = affected with trait
offspring are in birth order from left to right
I = parent gen
II = offspring