Meiosis: production of gametes

Meiosis I

1. homologous chromosomes synapse.

2. crossing over occurs

3. reduction division (homologous chromosomes separate)

Meiosis II

1. begins with two haploid cells with twice the normal amount of DNA

2. sister chromatids separate

3. Result: four haploid gametes.

Genetics: study of heredity (information passed down from parents to offspring)

progeny: offspring

Each person has half their DNA from father and half from mother. Heredity and the effect of the environment affect who and what we are.

In order for each organism to receive half its DNA from mom and half from dad, MEIOSIS AND FERTILIZATION must occur.

Mendel: father of genetics. an Austrian monk who studied inheritance in pea plants.

homozygous: true breeding. contain two of same trait.

heterozygous: contains two different alleles.

alleles: alternate forms of a gene.

P generation: parental generation

F₁ generation: first filial generation

F₂ generation: second filial generation

Principles of Inheritance

1. Principle of Dominance and Recessiveness

a. Dominant: if the dominant allele is present, it will be seen (use capital letters: TT)

b. Recessive: allele that is masked by dominant allele. two recessive alleles must be present to show recessiveness (use lowercase letter: tt)

P: TT (tall) x tt (short)

2. Principle of segregation: alleles separate during meiosis. each gamete gets one copy of every gene.

3. Principle of Independent Assortment: dominant and recessive traits do not necessarily stay together.

Genotype: genetic makeup. TT, Tt, tt

Phenotype: physical appearance. tall, short

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