Inheritance of Traits

Traits

Characteristics or features that distinguish individuals from one another (e.g. hair colour, eye colour, height) They are inherited from generations before and are located on chromosomes. Genes are associated with the expression of traits

Heredity

The study of how traits are passed from one generation to the next

Genetics

The study of inheritance and genes

Chromosomes

Structures that carry genes and are associated with the expression of traits

Gregor Mendel

Scientist who established the principles of heredity through experiments with pea plants

Phenotypes

Observable traits in pea plants (e.g. tall/short, purple flowers/white flowers)

Crosses

Transfer of male gametes or pollen to female flowers for seed production

Parent Generation

Cross between purple and white flowered plants

F1 Generation (hybrids)

Offspring of the parent generation, all with purple flowers

F2 Generation

Offspring of the F1 generation, showing a 3:1 ratio of purple to white flowers

Allele

Different forms of the same gene, including dominant and recessive alleles. For every gene, you have 2 alleles.

Dominant allele

Expressed when two different alleles or two dominant alleles are present

Recessive allele

Only expressed when two copies are present

Homozygous

Having the same two alleles for a particular gene

Heterozygous

Having two different alleles for a particular gene

Mendel's Laws

Principles that determine dominance and recessiveness of traits

Law of segregation

Alleles segregate and divide during cell replication so that each gamete receives only 1 gene of each gene

Blood Types

Type O is recessive, types A and B are dominant, and A and B alleles together are codominant to create type AB

Expression of traits

Influenced by cellular interactions and environmental factors

Intelligence

A combination of genetics, environment, and other factors

Genotype

The specific genetic makeup

Gene

are made up of sequences of DNA and are arranged, one after another, at specific locations on chromosomes in the nucleus of cells.

Albinism

It is a recessive trait, if both parents have a dominant and a recessive allele there is a 25% change the child will have albinism

Dwarfism

It is a dominant trait. If One parents has a dominant and recessive allele and the other parent has 2 recessive alleles there is a 50% change the child will have a dominant allele expressing Dwarfism