Genetics

Heredity

Passing of traits from parents to offspring

Genetics

Study of how heredity occurs

Linked genes

genes that are located on the same chromosome

Unlinked genes

genes on different chromosomes

Genome

All genes on all chromosomes

Gene pool

All forms of all genes of human genome

Alleles

Form of a gene

Law of dominance

Alleles may be dominant or recessive

Genotype

Combination of alleles received from both parents

Types of genotypes

• homozygous dominant

• heterozygous

• homozygous recessive

Homozygous dominant

2 dominant alleles

• true/pure breeding

Heterozygous

1 dominant and 1 recessive

• carriers

Homozygous recessive

2 recessive alleles

• true/pure breeding

Phenotype

The expression of the genotype

Mendel's laws

• developed by Gregor Mendel

1. Law of unit characteristics

2. Law of dominance

3. Law of segregation

4. Law of independent assortment

Law of unit characteristics

• our traits are determined by genes that are found on our chromosomes

Law of segregation

• during meiosis alleles split (only 1 allele per gamete)

Law of independent assortment

• during anaphase genes on different chromosomes (unlinked) will migrate in different ways

Monohybrid crosses

crosses that examine the inheritance of only one specific trait

• complete dominance

• incomplete dominance

• co-dominance

• multiple alleles

• lethal alleles

Complete dominance

one allele is completely dominant over another

Incomplete dominance

2 dominant traits, blending of traits

Co-dominance

2 dominant traits, both are expressed

Multiple alleles

More than 2 alleles

Lethal alleles

Alleles that can cause death

Dihybrid crosses

crosses that examine the inheritance of two different traits