BIOLOGY: Topic 3 Flashcards
What was the early theory of inheritance?
Blending inheritance: Theory that phenotypes in offspring are a blend of both parents
What is the problem with blending inheritance?
The idea of blending inheritance eiminates any chance of genetic variance as extreme phenotypes would be eliminated from the population.
What theory is August Weismann known for?
Germ plasm theory for multi-cellular organisms: States that genetic information is transmitted only by germ cells in the gonads; all the other cells of the body do not transmit such information.
Who is Gregor Mendel?
the daddy of modern genetics
Define gene.
A gene is a sequence of DNA that codes for a protein, or phenotype.
Define locus
A locus is a specific location on a chromosome; it may or may not contain a gene.
Define allele
An allele a unique variant of a gene that differs in nucleotide sequence. (One allele from mom and one from dad)
What are Mendel’s three laws?
Dominance, segregation, and independent assortment
What does the law of independent assortment accomplish?
The law of independent assortment follows two traits at the same time, producing dihybrid crosses, which in turn determine whether a trait is inherited independently or dependently (in respect to another trait).
Define population
A group of species > 1 that lives in the same region and that interbreed.
Define Hardy-Weinberg
“p^2+2pq+q^2”
1- Under certain conditions, there is a predictable relationship between allele and genotype frequencies in a population, which are expressed as the HW equation.
2- Mendelian inheritance does not alter allele or genotype frequencies across generations in a population, allele and genotype frequencies remain constant.
What are the 6 assumptions made under HW?
- Diploid locus
- Random mating with respect to the locus
- no natural selection at the locus
- no mutation at the locus
- no migration
- no genetic drift
