vocabulary word definitionother things to know… the field of biology devoted to understanding how...

Vocabulary Word

Definition Other Things to Know…

The field of Biologydevoted to understanding how traits are passed from parents to offspring

Gregor Mendel-pioneer in genetics-crossed peas toshow how traitswere passed on

Genetics

• 22 pairs of chromosomes that are not sex chromosomes

Autosome

Vocabulary Word


A segment of DNAthat contains codingfor a protein – a unit of hereditary information

Found on chromosomes within the nucleus

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

http://www.nlm.nih.gov/exhibition/visibleproofs/media/detailed/vi_a_201.jpg

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


An allele that is masked by the presence of anotherallele for the sametrait

-Shown with a lower case letter(ex: a, t, g).-Will only be seen if both alleles for a traitare 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


The external (physical)appearance of an organism that is determined by theindividual’s genotype

Written as thePhysical Trait:

Brown hair, blue eyes, short, etc.

Phenotype

Vocabulary Word


The genetic makeupof an organism Written with the

letters of alleles:

Aa, TT, bb, etc.

Genotype

Vocabulary Word


Referring to a genepair in which the two alleles do notcode for the same trait

Written as: Aa

Heterozygous

Vocabulary Word


An organism that ishomozygous for a trait

Ex: AA or aa

Purebred

Vocabulary Word


An allele that masksthe presence ofanother allelefor the same trait

-Shown with a capital letter(ex: A, T, G).-Will always be seen if present.

Dominant

Vocabulary Word


The number of timesan event is expectedto happen dividedby the number of opportunities of an event to happen

Ex: dice, coin-flipping, chance of haveblue eyes, etc.

Probability

Vocabulary Word


An alternate formof a gene

(An alternate form of a trait.)

Ex: Everyonehas 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


The transmission oftraits from parents to their offspring

Important for understanding reasons for ourappearance andstudy of geneticdiseases

Heredity

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

Multiple Alleles

Vocabulary Word


A model used to establish the probabilities of theresults of a geneticcross

Mom’s allelesgo together on one side and Dad’s go togetheron the other.

PunnettSquare

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

Test cross

Vocabulary Word


Law stating that pairs of genes separate in meiosisand each gamete receives one gene of a pair

Allows each parent to contribute half thechromosomes to produce offspringwith the full # ofchromosomes.

Law ofSegregation

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

Autosomal

Vocabulary Word


Referring to a genepair in which the two alleles code for the same trait

Written as:AA or aa

Homozygous

Vocabulary Word


A category withinwhich alternatecharacteristics can be observed

Examples of traits:

hair color, eye color,

height

Vocabulary Word


An organism thatis 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


Law stating that pairs of genesseparate independently of one another in meiosis

The gene for eye color sorts separately from hair color, and skin color, etc…

Law ofIndependentAssortment

vocabulary word definitionother things to know… the field of biology devoted to understanding how...

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