Mendelian Genetics + Types of Inheritance

Trait

A characteristic that an organism can pass on to its offspring

Heredity

the passing of traits from parents to offspring

Genetics

the science and study of heredity

Monohybrid cross

a cross involving a single trait (ex. Flower Color)

Dihybrid cross

a cross involving two traits (ex. Flower Color + Seed Color)

Dominant Allele

is expressed regardless of another present represented by upper letter (B)

Recessive Allele

is expressed when two of the same allele is present. The expression is "hidden" if dominant allele is represented by lower letter (b)

Phenotype

the physical feature(s) resulting from a specific combination of alleles ex. purple flowers, yellow seeds

Genotype

represented the allele combination for a trait can reveal details that are not present in the phenotype or physical appearance

Homologous

genotypes that carry two of the same alleles

Hybrids or Heterozygous

Genotypes with different copies (dominant + recessive)

Father of genetics

Gregor Mendel

What did Mendel discover?

Genes pass on heritable traits (alleles) from parents to offspring

True breeding parents

They consistently produce offspring with a single trait (allele)

The Phenotype + Genotype (BB, Bb)

HD + HZ, Same phenotype

The law of segregation

When an organism makes gametes, each gamete receives just one gene copy, which is selected randomly

If there are two alleles, for one zygote which allele will be expressed?

The dominant allele

Incomplete dominance?

A blending of traits. Red+White\=Pink.

Difference in incomplete dominance

No dominant/recessive trait because both are of equal importance

Codominance?

two alleles are equally expressed in heterozygous individuals

Examples of codomiance inheritance in humans?

Blood type

What two types of inheritance have the same genotype (in punnet squares) but different phenotypes?

Incomplete Dominance + Codominance

Sex-linked trait

a trait controlled by genes on sex chromosomes

Trait carriers

X chromosome

Why are males more affected by recessive X-linked traits?

They only have one X chromosome, unlike female who replaces them with the other one.