NATS 1675 Lecture Notes - Lecture 10: Abo Blood Group System, Robert Crippen, Quantitative Trait Locus
Document Summary
Nats 1675 lecture #10 genetics part 3. Side note: allele is when two genes from homologous chromosomes are influencing the same trait. R/r y/y t/t(/ indicates meiosis) first the two r"s separate. They are separating independently of the r"s (mendels third law). Different phenotypes controlled by a single pair of genes. 2 or more pairs of alleles are necessary for a given phenotypic expression. Colour of skin, hair and eyes are examples of polygenic inheritance. More than the normal 2 alleles are present at a locus in a chromosome within the population. Abo blood groups are examples of multiple alleles. Cumulative effect (erroneously referred to as incomplete dominance) refers to the condition that hybrids are distinguishable from their parents, i. e. , red flowers (rr) x white flowers (rr) pink flowers (rr) In other words, the alternate forms of the alleles are neither dominant nor recessive, the phenotypic expression within a heterozygous offspring is a blend.
