Genetics Classroom Terminology Flashcards
Hybrids
The offspring of genetically dissimilar parents.
Also known as HETEROZYGOTES
Pure Breeding Lines
Families of organisms that produce offspring with specific parental traits that remain constant from generation to generation.
Example:
Pure breed poodles
Heterozygous
A genotype in which the two copies of the gene that determine a particular trait are different alleles.
Example:
Hybrids
Homozygous
A genotype in which the two copies of the gene that determine a particular trait are the same allele.
Dominant allele
An allele whose phenotype is expressed in a heterozygote.
Recessive Allele
An allele whose phenotype is NOT expressed in a Heterozygote.
Phenotype
An observable characteristic.
Allele
Alternative for of a single gene.
Gene
The basic unit of biological information. The specific segment of DNA in a discrete region of a chromosome that serves as a unit of function by encoding a particular RNA or protein.
Genotype
The actual alleles present in an individual.
Incomplete Dominance
The expression of Heterozygous phenotype resulting in offspring whose phenotype is intermediate between those of the parents.
Codominant
Expression of HETEROZYGOUS GENOTYPE resulting in HYBRID offspring that resemble both parents equally for a particular trait.
Pedigree
An orderly diagram of a families relevant genetic features, extending through as many generations as possible.
Carriers
HETEROZYGOUS individuals of normal PHENOTYPE that have a RECESSIVE allele for a trait.
Wild Type Phenotype (+)
An allele or DNA variant whose frequency is more than 1% in a population. An allele that dictates the most frequently observed phenotype in a population.
Expressed as:
(+)
Haplo-insufficiency
A rare form of DOMINANCE in which an individual is HETEROZYGOUS for a wild type allele (WT) and a LOSS of FUNCTION allele show an abnormal phenotype because the level of gene activity is not enough to make a normal phenotype.
Epistasis
A gene interaction in which the effects of alleles at one gene HIDE the effects of alleles at another gene.
RECESSIVE epistasis
Special case of epistasis in which the epistasic allele is RECESSIVE.
Complementation
A process in which a HETEROZYGOUSITY for LOSS of FUNCTION mutant RECESSIVE alleles for TWO DIFFERENT genes that function in the SAME pathway produces a NORMAL PHENOTYPE.
Complementation Test
A method of discovering whether TWO MUTANTS are in the SAME or SEPARATE genes.
Cross Fertilization
Brushing the pollen from one plant onto the female organ of another plant.
Self Fertilizing (Selfing)
Fertilization in which both egg and pollen come from the same plant.
Parental (P) Generation
Pure breeding individuals whose progeny in subsequent generations will be studied for specific traits.
Testcross
A cross to determine the GENOTYPE of an individual showing a DOMINANT PHENOTYPE by mating with an individual showing the RECESSIVE PHENOTYPE.
Segregation
EQUAL separation of ALLELES for each trait during GAMETE formation; in which ONE allele of EACH gene goes to EACH GAMETE.
Cross
The deliberate mating of selected parents based on particular genetic traits desired in the offspring.
Zygote
The DIPLOID cell formed by the fertilization of the egg by the sperm during SEXUAL REPRODUCTION.
Gamete
Specialized HAPLOID cells (eggs and sperm or pollen) that carry GENES between generations.
Dihybrids
An individual that is HETEROZYGOUS for TWO different GENES.
Monohybrids
Individuals having TWO differs ALLELES for a SINGLE trait.
