Chapter 8 Flashcards
Differentiate between the 2 hypotheses of inheritance that were prevalent at the time of Mendel’s experiments
- The blending hypothesis: traits blend, they mix like paint, original traits never reappear in future generations.
- The particulate hypothesis: genetic traits from parents occurs in distant units, traits can reappear, traits can skip a generation, units remain separate/maintain individual identity
Provide basic details of Mendel’s model system (garden pea plants) and his experimental set-up/method
Mendel used manual pollination, he removed all the stamens from the flower, using brushes he was able to control which plants were fertilized with each type of pollen.
Define P generation
Parental (first generation)
Definition F1 generation
First FILIAL generation (offspring of the P generation)
Define F2 generation
Second filial generation, offspring after the F¬1 generation
Define Gene
Specific DNA sequence containing instructions for a certain characteristic
Define Allele
A version of a gene
Define Dominant
Allele that dominates when present with another allele
Define Recessive
Allele that does not dominate when present with another allele
Define Homozygous
Both alleles are the same (both dominant or both recessive)
Define Heterozygous
Two different alleles (one dominant and the other recessive
Define Genotype
The two alleles for a gene present in a genome
Define Phenotype
A physical trait based on a particular genotype
Define Mutation
change in a DNA sequence, Creates new alleles of a gene
Define Incomplete Dominance
Neither allele is dominant resulting in intermediate phenotype
Define Codominance
Both alleles are dominant, both phenotypes appear
Define Epistasis
one gene/protein functions UPSTREAM from another protein, thus another gene cannot contribute its phenotype in the absence if another gene. Think assembly line or lab puppies (if a gene says no color then it doesn’t matter what follows, there will be no color)
When 2 genes are “linked,” it means they are:
Genes that are located near each other on a chromosome are called linked genes. They are linked because they travel together during meiosis. This means they get packaged into the same gamete more often than not.
How do recombinant phenotypes arise when 2 genes are linked?
Recombination
Your mitochondrial DNA comes from your ___________. Why?
The egg cell contains mitochondria while the sperm does not contribute mitochondria to the zygote, thus the mitochondrial DNA comes from the mother in humans.
