Genetics in Agriculture Agricultural Science I

At the completion of this unit, students will be able to: Define genetics, and discuss its importance. Identify and discuss the contents of a genome. Distinguish heredity type, including genotype and phenotype. Describe genetic trait expression and prediction.

Asexual Production The production of young from only one parent No gametes involved (egg and sperm) Offspring are identical to parents Sexual Reproduction The production of young from two parents Involves gametes (egg and sperm) Offspring are similar to parents

Meiosis Similar events to mitosis (cell division) Occurs only in testes and ovaries to produce egg and sperm cells. Reduces the number of chromosomes to half the normal number. One replication followed by two cell divisions.

Spermatogenesis Occurs in testes Results in four equally sized sperm cells being produced

Oogenesis Occurs in ovaries Results in four different sized cells: One egg cell Three polar bodies

Definitions: Fertilization: union of egg and sperm; restores normal chromosome number Zygote: Fertilized egg Dominant: Trait that shows in a cross between two true-breeding parents Recessive: Trait hidden in a cross between two individuals

Definitions: Traits: characteristics that are inherited Heredity: The passing of traits from parent to offspring Genetics: The study of heredity and traits Pollination: Transfer of pollen grains to the female reproductive organ in flowers