Genetics

The production of young by only one PARENT No SEX Cells Asexual Reproduction The production of young by only one PARENT No SEX Cells Offspring are IDENTICAL to parents

The production of young by two PARENTS SEX cells (sperm and egg) Sexual Reproduction The production of young by two PARENTS SEX cells (sperm and egg) Offspring are SIMILAR to parents

GLEEPS

Production of Sex Cells (Meiosis) 1. SIMILAR events to mitosis 2. Occurs ONLY in the TESTES and OVARIES to produce egg and sperm cells. 3. REDUCES the NUMBER of chromosomes to half the normal number. 4. ONE replication followed by TWO cell divisions.

Meiosis

FERTILIZATION the union of the egg and sperm nuclei restores the normal chromosome number.

ZYGOTE a fertilized egg

SPERMATOGENESIS 1. occurs in TESTES 2. EQUALLY sized cells 3. FOUR sperm cells produced

Spermatogenesis

OOGENESIS 1. occurs in OVARIES 2. DIFFERENT sized cells 3. ONE egg cell produced and three POLAR bodies

Oogenesis

Horsefly Chromosome Lab

Patterns of Inheritance

DOMINANT the trait that SHOWS in a cross between two true-breeding parents Example in Cattle -- Black coat color, polled Example in Sheep -- White wool Example in Swine -- Black hair

Recessive the trait that is HIDDEN in a cross between two individuals. Example in Cattle -- Red coat color, horns, dwarfism Example in Sheep -- Black wool Example in Swine -- Red hair

PHENOTYPE the OUTWARD appearance of the organism

Genotype the actual GENE MAKEUP of an organism

Homozygous when both of the genes (letters) in the pair are the SAME Example -- TT or tt

Heterozygous when both of the genes (letters) in the pair are DIFFERENT Example -- Tt

Incomplete Dominance The genes are neither dominant nor recessive, but are equals Example -- Shorthorn Cattle WW=White RR=Red, RW=Roan