Meiosis

• specialized diploid cells splits in ½ 2x making 4 sperate cells

• 46 chromosomes (23- Maternal and 23 - Paternal)

• Haploid Cells - ½ of a full set of chromosomes

  • Egg and Sperm (gametes)

• Very similar to mitosis but done twice to produce 4 separate cells

Mendelian Genetics

• From Gregor Mendel

  • Crossed pea plants and made offspring from the original

• 1st cross - P (parental) cross

  • F1 cross - offspring

  • F2 cross - offspring x offspring

    • 3:1 ratio

• Law of Segregation

  • separation of the 2 alleles

    • 1:2 ratio of getting the genotype 50%

• Law of Independent Assortment

  • the alleles of two different genes get sorted into gametes independently of one another

• Diseases

  • Huntington’s Diseases

    • degeneration of nerve fibers

      • uncontrollable shakes and causes death

      • Dominant

        • use pedigree for family risk

      • don’t know abt it until mid-age

Non Mendelian Genetics

• do not follow the Mendelian rules

• Incomplete dominance

  • the phenotype of a heterozygous organism becomes a blend between the phenotypes of its homozygous parents'

  • none are dominant

    • 

• Codominance

  • both alleles are simultaneously expressed in the heterozygote (BW)

    • common in animals

  • both are dominant

  • 

• Sex-linked v Autosomal diseases

  • Sex-linked

    • mainly affects males more than females

    • maybe skipped a generation

  • Autosomal

    • affect both males and females equally

    • Dominant

      • traits from 1 parent

    • Recessive

      • traits from both parents

• Epistasis

  • When the phenotype of 1 gene at 1 alters the phenotype of another gene

    • albino mouses

    • Red hair

• Polygenic Inheritance

  • effect of 2 genes on 1 character

    • height, eye color, hair color

    • AaBbCc