Variation in Heredity (lesson seven)

Question 1

typical plants

Answer 1

Typical” being homozygous dominant

Question 2

atypical plants

Answer 2

“Atypical” being homozygous recessive

Question 3

Complete Dominance

Answer 3

• Complete dominance when one allele is expressed in the phenotype, even if there is another allele present
• the dominant allele’s phenotype is expressed even if the genotype is heterozygous

Question 4

do all traits follow complete dominance?

Answer 4

• Not all traits follow complete dominance though
• There are variations possible in the simple patterns that Mendel proposed
• Examples include:
• Incomplete Dominance
• Codominance

Question 5

Incomplete Dominance

Answer 5

• Incomplete dominance is when the 2 alleles interact with one another
• Neither mask the other, but instead result in a blended phenotype
• Snapdragons are a case of incomplete dominance
• There are two alleles for flower colour including red (c^R) and white (c^W)
  -Neither are dominant, so neither allele can mask the other

Question 6

Codominance

Answer 6

• Codominance is another example of what can happen when the two alleles interact with one another
• Both mask the other, so both show up in a mixed phenotype
  ex:
• There are two alleles for hair colour including red (C^R) and white (C^W)
• Both are dominant, so both hair colours appear

Question 7

Codominance and Dominance

Answer 7

• Human blood type is inherited through both a completely dominant and codominant pattern
• There are 4 major blood types: A, B, AB and O
• These blood types are inherited through 3 possible alleles: I^A, I^B and i
• Each of these allele codes for a different enzyme that places different types of sugars on the surface of red blood cells