GENETICS

Who is the Father of Genetics

Gregor Mendel

Gene

Section of DNA that codes for a characteristic

Allele

Different forms (versions) of the gene

Locus:
(think location)

Where the gene is found in the DNA molecule

Dominant Allele

Allele (version of a gene) always shown in the phenotype of all generations

Recessive Allele

Allele hidden/masked in the genotype when with a dominant allele in a generation

Phenotype:

The (physical) appearance or expression of a gene

Genotype:

The actual alleles in the gene

State Mendel’s Law of Segregation (2 marks, all or nothing)

Each trait is controlled by two factors (now known as alleles) situated on homologous chromosomes. When gametes are formed,, the two factors are seperated and a gamete will contain one of these two factors

Mendel's Second Law: Law of Dominance

When organisms with pure breeding contrasting traits cross, all individuals of the F2 generation will display the dominant trait.

Mendel's Third Law:  Law of Independent Assortment

The various ;factors’ controlling the different characteristics are separate entities, not influencing each other in any way and sorting themselves out independently during gamete formation.

Discontinous Variation

no intermediate phenotypes occur

Continuous variation

a range occurs

Monohybrid Cross

This is a type of cross where we only cross ONE characteristic

Nature

Variations that are influenced by what is inherited from the parents

Nuture

Variations that are influenced by the enviroment as the organisms grows and develops