Inheritance questions

Question 1

What is meant by codominence

Answer 1

When both alleles are expressed by phenotype

Question 2

Male cats with a tortoiseshell phenotype do not usually occur. Explain why.

Answer 2

Males only posses one allele
-can’t be reccesive

Question 3

Some breeders only breed for the dominant allele, what would happen to the alleles

Answer 3

• increase of homozygous dominant
• decrease of homozygous recessive

Question 4

Some scientists use the restriction enzyme on each dn strand

Answer 4

Cut at same base sequence
So all code for R

Question 5

Explain what it means for genes to be linked

Answer 5

They have 2 genes on the same chromosome

Question 6

Use your knowledge of gene linkage to explain the results
975, 963,186,194
On GgNn

Answer 6

-mainly Gn and gn produced
-when crossed over few Gn and gN
-so few ggNn

Question 7

Explain the advantage of presenting results as a ratio?

Answer 7

• allows to validly compare

Question 8

give 2 causes of genetic variation

Answer 8

• crossing over
  -random fusion of gametes
  -random fertilisation

Question 9

Do autosomal alleles cross over

Answer 9

no

Question 10

Why arnt the observed phenotype ratios not the same as expected

Answer 10

-random fertilisation
-small sample size