12-Mendelian Genetics

What did Gregor Mendel do?

discovered basic rules of inheritance; foundation of genetics

what did Gregor Mendel experiment with?

peas

advantages of experimenting on peas

inexpensive, many varieties of peas, short generation = many offspring, easy to control pollination

stamen =

male

Carpel =

female

self-fertilization

When pollen fertilizes eggs from the same flower

what did mental remove from the flower to prevent self-fertilization?

stamen

how did mental cross-fertilize flowers?

transferred pollen from one flower to another

what is an example of a characteristic?

seed texture

what is an example of a trait?

purple or white flower color

what kind of method did mental apply?

quantitative

what was very important to Mendel's work that he developed?

developed true-breeding lines

true-breeding lines

interbred members always produce offspring with the same phenotype

blending inheritance hypothesis

Gametes contain sampling of fluids from parents bodies

what were the problems with the bending inheritance hypothesis?

populations don't become uniform and traits 'skip' a generation

Mendel crossed true-breeding plants with _______ traits

contrasting

Particulate Inheritance Hypothesis

characteristics passed from gen to gen by discrete particles (genes)

Mendel's Model

genes are discrete units of information, 2 alleles from each parent (2n), allele from one parent masks expression of allele from another parent

Gene

basic unit of heredity, codes for a protein, at a specific locus

Alleles

alternative versions of a gene

Genotype

genetic makeup of an organism

for each characteristic, individual inherits __________

2 alleles

Homozygous

An organism that has two identical alleles for a trait

Heterozygous

An organism that has two different alleles for a trait

Mendel's Laws of inheritance

law of segregation and law of independent assortment

Law of Segregation

Mendel's law that states that the pairs of homologous chromosomes separate in meiosis so that only one chromosome from each pair is present in each gamete

law of independent assortment

2 or more genes assort independently during gamete formation --> each pair of alleles segregates independently of all other alleles

independent assortment + crossing-over =

lots of genetic variation

A punnet square shows

all the posible outcomes of a genetic cross

monohybrid cross

a cross in which only one characteristic is tracked

Phenotype

physical characteristics of an organism

test cross

determine genotype of dominant phenotype

dihybrid cross

follows 2 characteristics

dihybrid cross only works if what?

alleles are on different pairs of homologs

probability of an event =

expected frequency

multiplication rule for independent events

occurrence of one event does not affect probability that other event will occur

Addition for mutually exclusive events

events cannot occur simultaneously (If one event happens, the other cannot)