BIO A01 - punnett square (Module 3 L8)

punnett squares, course: BIO A01, Lecture 8

Transmission genetics

manner in which genetic differences among individuals are passed from generation to generation.

PEA PLANT CROSSING

• Pea flowers have sperm- and egg-producing structures that allow for self-fertilization to occur.
• Mendel had to remove sperm-producing structures in order to ensure that only his
intended cross would happen

reciprocal crosses

Mendel interchanged which parent (male or female) exhibited each
trait.

hereditary factor

A hereditary factor is a unit of inheritance that determines a specific trait.

alleles

The different forms of a gene are

genotype

The combination of alleles in an individual is its
genotype

phenotype.

the expression of the trait is its
phenotype.

The Principle of Segregation:

the equal
separation of alleles of a
gene into different gametes;
half get one allele, the other
half get the other allele

SEGREGATION OF ALLELES IN MEIOSIS

incomplete dominance

two alleles blend to create a new phenotype,

CODOMINANCE

a type of inheritance where two different versions of a gene (alleles) are expressed equally

eg blood cells

Multiplication rule:

outcomes can occur simultaneously and the occurrence
of one does not impact the likelihood of the other

addition rule

possible outcomes cannot occur simultaneously.

Independent
Assortment:

segregation of
one set of alleles of a gene pair
is independent of the
segregation of another set of
alleles of a different gene pair.

do all genes undergo independant asssortment

genes close together on the same
chromosome = linked genes; do NOT assort
independently

Epistasis:

two genes
interacting affect the same trait

eg chicken with colour but w inhibiton gene