14.1 Flashcards
Character
A heritable feature that varies among individuals.
Trait
Each variant for a character.
True-Breeding
Individuals that are homozygous for every gene.
Any crosses performed will result in offspring with the same phenotype.
Hybridization
The mating/crossing of two true-breeding varieties.
What was the explanation of heredity that was favored during the 1800s?
“Blending” Hypothesis
What is Mendel’s Model?
It is a model to explain the 3:1 inheritance pattern among the F2 offspring.
What are the four related concepts that make up Mendel’s model?
- Alternative versions of genes account for variations in inherited characters.
- For each character, an organism inherits two versions of a gene – one from each parent.
- If two alleles at a locus differ, then the dominant allele determines the organism’s appearance and the recessive allele has no noticeable effect on the organism’s appearance.
- The Law of Segregation
Law of Segregation
The two alleles of a heritable charater separate during gamete formation and end up in different gametes.
Test Cross
Breeding an organism with a dominant phenotype, of unknown genotype, with a recessive homozygote.
Can reveal the genotype of the organism.
Monohybrids
Heterozygous for the one character followed in the cross.
Monohybrid Cross
A genetic cross where one trait is followed.
Dihybrids
Heterozygous for the two characters followed in a cross.
Law of Independent Assortment
Two or more genes assort independently – Each pair of allleles segregate independentyle of any other pair of alleles – during gamete formation.
Where does the “Law of Independent Assortment” apply?
- Genes located on different (non-homologous) chromosomes
- Genes that are very far apart on the same chromosome.
