Vocabulary Word DefinitionOther Things to Know… The field of Biology devoted to understanding how traits are passed from parents to offspring Gregor Mendel -pioneer in genetics -crossed peas to show how traits were passed on

Genetics

22 pairs of chromosomes that are not sex chromosomes

Autosome

Vocabulary Word DefinitionOther Things to Know… A segment of DNA that contains coding for a protein – a unit of hereditary information Found on chromosomes within the nucleus

Gene

Founder of genetics (study of heredity) Monk who lived in a monastery

Gregor Mendel

individuals who has one copy of a recessive allele –Does not express trait but they “carry” it

Carrier

A family history that shows a trait that is inherited over several generations

Pedigree

Vocabulary Word DefinitionOther Things to Know… An allele that is masked by the presence of another allele for the same trait -Shown with a lower case letter (ex: a, t, g). -Will only be seen if both alleles for a trait are recessive.

Recessive

Trait found on x or y chromosome

Sex-linked

Both alleles for a gene are expressed in a heterozygous offspring –Neither allele is dominant or recessive – no blending!

Co-dominance

Vocabulary Word DefinitionOther Things to Know… The external (physical) appearance of an organism that is determined by the individual’s genotype Written as the Physical Trait: Brown hair, blue eyes, short, etc.

Phenotype

Vocabulary Word DefinitionOther Things to Know… The genetic makeup of an organism Written with the letters of alleles: Aa, TT, bb, etc.

Genotype

Vocabulary Word DefinitionOther Things to Know… Referring to a gene pair in which the two alleles do not code for the same trait Written as: Aa

Heterozygous

Vocabulary Word DefinitionOther Things to Know… An organism that is homozygous for a trait Ex: AA or aa

Purebred

Vocabulary Word DefinitionOther Things to Know… An allele that masks the presence of another allele for the same trait -Shown with a capital letter (ex: A, T, G). -Will always be seen if present.

Dominant

Vocabulary Word DefinitionOther Things to Know… The number of times an event is expected to happen divided by the number of opportunities of an event to happen Ex: dice, coin-flipping, chance of have blue eyes, etc.

Probability

Vocabulary Word DefinitionOther Things to Know… An alternate form of a gene (An alternate form of a trait.) Ex: Everyone has an eye color, but there are different types: blue, brown, etc.

Alleles

A cross between two organisms where two genes are studied

Dihybrid Cross

Vocabulary Word DefinitionOther Things to Know… The transmission of traits from parents to their offspring Important for understanding reasons for our appearance and study of genetic diseases

Heredity

Traits can be controlled by genes with three or more alleles.

Multiple Alleles

Vocabulary Word DefinitionOther Things to Know… A model used to establish the probabilities of the results of a genetic cross Mom’s alleles go together on one side and Dad’s go together on the other.

Punnett Square

An individual of unknown genotype is crossed with a homozygous recessive individual to determine genotype

Test cross

Vocabulary Word DefinitionOther Things to Know… Law stating that pairs of genes separate in meiosis and each gamete receives one gene of a pair Allows each parent to contribute half the chromosomes to produce offspring with the full # of chromosomes.

Law of Segregation

Pedigree - use only 2 alleles (ex. BB, Bb, bb), trait not found on a sex chromosome

Autosomal

Vocabulary Word DefinitionOther Things to Know… Referring to a gene pair in which the two alleles code for the same trait Written as: AA or aa

Homozygous

Vocabulary Word DefinitionOther Things to Know… A category within which alternate characteristics can be observed Examples of traits: hair color, eye color, height

Trait

Vocabulary Word DefinitionOther Things to Know… An organism that is heterozygous for a trait Ex: Aa

Hybrid

When 2 or more alleles influence the phenotype –Results in a phenotype intermediate between the dominant and recessive trait

Incomplete Dominance

Vocabulary Word DefinitionOther Things to Know… Law stating that pairs of genes separate independently of one another in meiosis The gene for eye color sorts separately from hair color, and skin color, etc…

Law of Independent Assortment