Alleles and Gene

What is Genetics?

Genetics is the study of heredity, which is the passing of traits from one generation to another.

Are a sequence in DNA that code for a protein, thus for a specific traits

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Genes

Alleles are different possibilities for a given trait!

• Every trait has two alleles. One from mother and one from father.

• Ex: blue/black eyes, brown/blonde hair, tall/short

​Alleles?

Traits are specific characteristics that varies from one individual to another.

• Blue eyes

• Brown hair

• Tall

Traits?

An organism with a recessive allele combination will only exhibit that trait when the dominant allele isn't present.

• Represented by a lowercase letter "r"

Recessive

Is stronger so it masks the other trait if present.

• Represented by a capital letter "R"

Dominant

Genotype: The genetic makeup of an organism. The gene (or allele) combination an organism has.

• Examples: Tt, SS, Bb, aa

Phenotype: The physical characteristics of an organism

• Examples: Tall or short, Straight hair or wavy hair...

Homozygous - Term used to refer to an organism that has two IDENTICAL alleles for a particular trait. Considered as purebred! EXAMPLE: TT or tt

Heterozygous - Term used to refer to an organism that has two DIFFERENT alleles for a particular trait. Considered as hybrids.

EXAMPLE: Tt