Mendel

1
Mendels Laws
2
What we already know

• Inheritable factors or genes are responsible
  for all heritable characteristics
• Phenotype is based on Genotype
• Each trait is based on two genes, one from the
  mother and the other from the father
• True-breeding individuals are homozygous (both
  alleles are the same)

3
Mendels Laws Unit Factors

• The appearance of each plant was determined by
  two inheritance factors
• Each organism has two alleles for each trait

4
Mendels Laws Rule of Dominance

• Inheritance factors can be either dominant or
  recessive
• Observed traits are dominant, traits that
  disappear are recessive
• Homozygous Dominant (TT) two dominant alleles,
  shows dominant trait
• Homozygous Recessive (tt) two recessive alleles,
  shows recessive trait
• Heterozygous (Tt) has one dominant allele and
  one recessive allele, shows dominant trait

5
Mendels Laws Law of Segregation

• Inheritance factors separate randomly when sex
  cells are formed
• This means each parent can only pass on ONE copy
  of their two genes to each offspring
• This is RANDOM, like the flip of a coin

6
Mendels Laws Law of Independent Assortment

• Inheritance factors for different traits are
  passed from parents to their offspring
  independently of one another
• Genes for different traits are inherited
  independently of each other
• Genes for different traits are often on different
  chromosomes, which separate according to the law
  of segregation when gametes are formed