Bio 1115- Chapter 14 (genetics and mendel)

Genetics

The scientific study of heredity

Heredity

Passing of traits from parents to offspring

genes

DNA segments that serve as the key functional units in hereditary transmission.

alleles

Different forms of a gene

pure lines

produce identical offspring when self-pollinated

parental generation

the adults used in the first experimental cross of a breeding experiment

F1 generation

the first generation of offspring obtained from an experimental cross of two organisms

F2 generation

offspring of the F1 generation

genotype

genetic makeup of an organism

phenotype

An organism's physical appearance, or visible traits.

Heterozygous

An organism that has two different alleles for a trait

Homozygous

A cell or organism that has two of the same alleles for a particular trait (AA and aa)

dominant allele

An allele whose trait always shows up in the organism when the allele is present.

recessive allele

An allele that is masked when a dominant allele is present

independent assortment and principles of segregation

two principles of inheritance

independent assortment

alleles of different genes are distributed independently of one another

principles of segregation

org. = two alleles for each gene but can only pass one

Punnett Square

segregation of alleles --> gametes and how they pair up during fertilisation

monohybrid cross

heterozygous mating --> single gene = same allele (self-fertilisation)

reciprocal crosses

A pair of matings in one of which a female of genotype A mates with a male of genotype B and in the other of which a female of genotype B mates with a male of genotype A.

3:1 ratio

monohybrid and reciprocal crosses pattern

dihybrid cross

two heterozygous (same genes) for two genes

--> alleles of diff. genes = segregated together or independently

bricks and mortar model

indi. = characteristics --> through out life --> collected physical sub. related characteristics --> because of reproductive organs

blueprint model

process of heredity = X directly transmit traits BUT INFO on traits

Gregor mendel hypothesis

1. blending hypothesis

2. inheritance of acquired characteristics hypothesis

blending hypothesis

parental traits blend --> offspring = INTERMEDIATE traits

ex. blue and red = purple

- variation = lost over time

inheritance of acquired characteristics

indi. traits = MODIFIED over lifespan = passed --> offspring

polymorphic trait

A trait that exists in two or more forms

cross-fertilisation/outcrossing

Gamates of two different individuals come together to form off springs

One flower pollen fertilizes a whole different flower

hypothesis of particulate inheritance

hereditary determinants DO NOT blend/change through use = discrete unchanged particles

independent assortment and meiosis

Independent assortment happens during meiosis, specifically in metaphase I

law of segregation and meiosis

The Law of Segregation is directly connected to meiosis, specifically during anaphase I

multiplication rule

probability --> two or more INDEPENDENT events occur together = individual probabilities

addition rule

probability --> ANY two or more exclusive events occur = adding their probabilities