Genotype, Phenotype & Patterns of Inheritance

Question 1

What environmental factors can influence genotypes and phenotypes?

Answer 1

Radiation, mutagens, chemicals, diet, life-style

Question 2

Describe autosomal dominant inheritance

Answer 2

Gene located on autosome, heterozygotes affected, equal between sexes, rare in homozygotes, can’t skip generations, 50% chance of an affected child

Question 3

Describe autosomal recessive inheritance

Answer 3

Gene located on autosome, heterozygotes affected, equal between sexes, 25% of an affected child (2 x homozygotes), can skip generations

Question 4

Describe X-linked recessive inheritance

Answer 4

Gene on X chromosome, hemizygous and homozygous females affected, more common in males, males cannot pass it on, daughters of affected males are heterozygous

Question 5

Draw out pedigree symbols

Answer 5