Extending Mendelian Genetics (20)

Question 1

Recognise and explain the molecular basis of different dominance relationships between alleles within a gene

Answer 1

Co-dominance and incomplete dominance - phenotype of heterozygotes
Complete dominance - heterozygous and homozygous phenotypes

Question 2

Distinguish between incomplete dominance, co-dominance, multiple alleles, epistasis, polygenic inheritance, and sex-linked genes

Answer 2

Incomplete dominance - intermediate inheritance in which one allele for a specific trait is not completely expressed over its paired allele
Co-dominance - alleles of a gene pair in a heterozygote are fully expressed. This results in offspring with a phenotype that is neither dominant nor recessive
Multiple alleles - Three or more alternative forms of a gene (alleles) that can occupy the same locus
Epistasis - when two or more different gene loci contribute to the same phenotype
Polygenic inheritance - One characteristic is controlled by two or more genes
Sex-linked genes - genetic linkage has to do with the X and Y sex chromosomes (not only carry the genetic traits but also the characteristic)