16.4

Question 1

beyond mendel

Answer 1

mendels model of inheritcance assumes
–each trait is controlled by 1 gene
–each gene only has 2 alleles
–a clear dominant-recessive realtionship between alleles

Question 2

multiple alleles

Answer 2

may be more than 2 alleles for a gene in a population
each diploid individual can only have 2 alleles

Question 3

ABO blood typing

Answer 3

3 different alleles for expressing antigens on surface of blood cells
I^A allele (domiant)
I^B allele (domiant)
i allele (recessive)

4 possible phenotypes
-i is recessive (no surface antigens present)
- I^AI^B expresses both surface antigens

Question 4

Rh blood typing

Answer 4

-R allele (dominant)
–Rh antigen present
-r allele (recessive)
-no antigen present

Question 5

polygenic inheritance

Answer 5

phenotype is accumulation of contributions by multiple genes
traits show continous varation: termed quantiative traits

Question 6

pleiotropy

Answer 6

one gene impacts multiple phenotypes
multiple symptoms can be traced back to one allele
difficult to predict
“cystic fibrosis”

Question 7

incomplete dominance

Answer 7

incomplete dominance
heterozygous is intermediate phenotype between homozygoutes
red flowers x white flowers= pink

Question 8

codominance

Answer 8

heterozygous shows aspects of both homozygous phenotypes