Genetics Genetics VocabularyVocabulary

GeneticsGenetics

- - the study of hereditythe study of heredity

Gregor Mendel-father of genetics.

HeredityHeredity

The passing of The passing of traits from traits from parents to parents to offspring.offspring.

TraitTrait The specific forms The specific forms

of a characteristic of a characteristic that are passed on that are passed on to offspring to offspring through genes.through genes.

GeneGene A set of instructions A set of instructions

for an inherited for an inherited trait.trait.

ChromosomeChromosome

Carries genetic Carries genetic information that information that controls inherited controls inherited characteristics characteristics such as eye color.such as eye color.

AlleleAllele

The different forms of a gene, such The different forms of a gene, such as dominant or recessive, as dominant or recessive, represented by a letter.represented by a letter.

Dominant is uppercase letter …….TDominant is uppercase letter …….T Recessive is lower case letter…….tRecessive is lower case letter…….t

Dominant alleleDominant allele An allele whose An allele whose

trait is always trait is always visible when the visible when the allele is present.allele is present.

Recessive alleleRecessive allele An allele whose An allele whose

trait is only visible trait is only visible when the dominant when the dominant allele is not allele is not present.present.

RR

rr

Heterozygous Heterozygous (Hybrid)(Hybrid) Two different Two different

allelesalleles (one dominant, one (one dominant, one

recessive)recessive) Example:Example:

RrRr

Homozygous Homozygous (purebred)(purebred)

Two of the same Two of the same allelesalleles

(both dominant or (both dominant or both recessive)both recessive)

Example:Example:

RR RR oror rr rr

PhPhenotypeenotype The The phphysical ysical

characteristic of a characteristic of a person (visible person (visible trait)trait)

GenGenotypeotype The The gengenetic etic

makeup or allele makeup or allele combinationscombinations

RR

rr

ProbabilityProbability The chance that The chance that

something will something will happen.happen.

Punnett squarePunnett square A chart that shows A chart that shows

all possible all possible combinations of combinations of alleles that can alleles that can result from a result from a genetic cross. genetic cross.

PedigreePedigree

A tool for tracing traits through A tool for tracing traits through generations of a family.generations of a family.

1/2 colored-carrier1/2 colored-carrier boy-boy-squaresquare

colored-has traitcolored-has trait girl-circlegirl-circle empty-does not have traitempty-does not have trait

Incomplete Incomplete dominancedominance When one trait When one trait

doesn’t dominate doesn’t dominate over the other but over the other but both alleles have an both alleles have an influence on the influence on the trait.trait.

Blends traitsBlends traits

Co-dominanceCo-dominance A condition where A condition where

neither allele is neither allele is dominant and both dominant and both alleles are alleles are expressed in the expressed in the offspring. offspring.

Both traits appearBoth traits appear

Selective breedingSelective breeding Process for Process for

selecting certain selecting certain organisms to obtain organisms to obtain a specific trait.a specific trait.

EX:EX: Small dogSmall dog Fast dogsFast dogs Short hair catsShort hair cats Fast horsesFast horses

Genetic Genetic EngineeringEngineering Genes from one Genes from one

organism are organism are transferred into the transferred into the DNA of another DNA of another organism.organism.

EX:EX: Insulin-human DNA Insulin-human DNA

into bacteriainto bacteria medsmeds