Punnett Square

• mendelian chose a pea plant because

  1. can control mating pea plants
  2. easily self pollinated
  3. can reproduce many offspring (across many generations)
  4. have simple traits (one gens, two alleles for that gene)
• pure breed

  
• hybrid

  
• p gen= parent generation
• F1= first generation
• heterozygous = carrier
• mendelian attempted to cross purple and white = pure breed
• law of dominance= one trait dominates the other
• organisms caarries two copies of a gene (allele)
• law of segregation- two traits can be carried but only 1 gets passed on
• genotype- made up of 2 alleles
• gametes

  
• genotype

  
• possible zygotes

  
• HH x hh = hybrid
• genes that are carried by either sex chromosome are said to be sex linked
• men normally have an X and a Y- combination of sex chromosomes but women have two X's
• since only men inherit Y chromosomes they are onely ones to inherit Y-linked traits
• Biggest punnett square in a sex linked inheritance is- 2x2
• one geene causes a trait
• traits are always independent of each other
• incomplete dominance- third phenotype
• a allele for a specific trait is not completely expressed over its paired allele- incomplete dominance
• incomplete dominance is a blend of two traits
• product is a 3rd phenotype- incomplete dominance
• codominant inheritance- both genes are equally expressed
• blood type A, B, AB, O
• type O

  
• TYPE B

  
• TYPE A

  
• label the type of blood:

  
• polygenic inheritance- occurs when one characteristic is controlled by two or more genes
• co-dominance- two alleles are equally expressed