Genotype and Phenotype

Phenotype

-The external (or internal) appearance of an organism. -Strongly affected by the environment! --> Environment affects on phenotype are NOT passed on through inheritance -The manifested structure, function, and behaviors of an individual. -The expression at the genotype of an organism

Every individual carries to alleles of all possible alleles in the population

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Most traits are controlled by many genes and are more difficult to follow across generations.

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Alleles

Alternative versions of a gene that code for the same trait Every individual has two alleles (One maternal and one Paternal) that interact to produce the phenotype. the phenotype can be: -Homozygous Dominant -Homozygous Recessive - Can be Heterozygous Dominant and Recessive P.S. Exception: Both parents have blue eyes and child has brown eyes.

Dominance

Describes how the protein products of alleles interact in the phenotype 1. Spectrum of interaction between protein products of different alleles... ranges from complete to incomplete to codominance 2. Spectrum of interaction between protein products of different alleles...ranges from complete to incomplete to codominance 3. Dominant allele does NOT imply more common allele (half of them is expressed: codominance)

Codominance

Heterozygote expresses both homozygous phenotypes equally

Incomplete Dominance

Heterozygote has an intermediate phenotype between either homozygote. - So, neither dominant nor recessive traits are completely expressed, both are in a way, but blend with each other.

Complete Dominance

Heterozygote resemble homozygous dominant dominant trait takes over the recessive trait so the recessive is NOT expressed at all. --> it is the interaction between protein products of difference alleles, pathway form protein to phenotype is where dominance is reflected. Dominance doesn't imply more common allele!

What do single genes demonstrate?

Single genes demonstrate simple inheritance are easy to follow!

Genotype

The genetic make-up of an organism. The set of alleles at the gene The genes that an organism carries for a particular trait, also, collectively an organism's genetic composition Normal (G/G) Carrier (G/A) Disease (A/A)

Heterozygous

Two different alleles for the gene (Ex: Aa, or aa' or Aa' or Aa" aa"... )

Homozygous

Two of the same alleles for the gene (Ex: AA, aa or a'a' or a"a")