Other Patterns of Inheritance

1
Other Patterns of Inheritance

• Mendels experiments were successful because
• Simple relationships between genotypes
  phenotypes.
• Centered around complete dominance.
• Each gene was located on different chromosome.

2
Intermediate Inheritance

• Complete Dominance doesnt always occur.
• Some characters are due to mixtures.

3
X
4

• Incomplete Dominance
• Heterozygote offspring are intermediate between
  homozygous parents.
• Pink snapdragons Red white parents.
• Traits arent blended red white alleles are
  expressed equally but not fully.

Notice how these genes are written differently
from complete dominance. These have
superscripts The C stands for color and the
superscript tells which allele is present (red or
white)
5

• CODOMINANCE
• Both alleles in a heterozygote are expressed
  fully at the same time.
• Blood type A x B AB
• Shorthorn cattle. Red bull x white cow roan
  offspring.

6

• POLYGENIC TRAITS
• These are traits controlled by more than one
  gene.
• The phenotype may be a complex combination to
  produce the trait.
• All of these genes work together
• Human eye color, skin color, hair color, and
  height are examples.

7
Blood type is an example of both multiple
alleles and codominance.
Just for fun Blood bag CANDY???
8

• Multiple Alleles
• Trait may be controlled by more than one allele.
• Blood types are controlled by the alleles
• IA type A blood (codominant with type B)
• IB type B blood (codominant with type A)
• i type O blood
• There may be different alleles for a gene but an
  individual only has one.

IA i
IB IAIB IBi
i IAi ii
9
(No Transcript)
10

• Rh negative mother
• Rh positive fetus
• 2nd or later pregnancies
• May cause Erythroblastosis Fetalis
• Treatment Rhogam injection after each pregnancy
  and each miscarriage.