Lab Chapter 4 Flashcards
The rusty crayfish has a ______ impact on ontario’s native crayfish because…
negative
rusty crayfish outcompete the native crayfish for food and shelter
allozyme loci
different molecular forms of an enzyme that correspond to different alleles of a common gene (locus)
Genetic variation
is necessary for the evolution or adaptations by natural selection
selection
is a natural process, many of the forces that are sources of stress for the Great Lakes fish communities are of human origin
Examples
- size-selective fishing gear
- habitat elimination
- alteration of prey species
- pollution stresses
gene flow
is the exchange of alleles between neighbouring populations
Distance between populations are affected by…
increases or decreases in population densities
genetic drift is most pronounced in…
small populations
4 Limitations of estimating genetic variation with Mendelian method
1) restricted to phenotypic characters
2) too time consuming
3) does not yield precise info on genotypes (homozygous dominant vs. heterozygous)
4) too many gene loci in most organisms for this process to yield reliable estimates of gene variation
How to overcome 4 Limitations of estimating genetic variation with Mendelian method
use the techniques of molecular genetics
Allozymes
mutations that result in differences in electrophoretic mobility of the corresponding enzymes (different forms of enzymes)
monomeric enzymes
enzyme that produces one polypeptide chain, which is a fully functional protein
dimer
a single polypeptide chain that is produced by each allele
polymorphism (P)
the proportion of loci examined that show evidence of more than one allele
Heterozygosity (H)
the average frequency of heterozygous individuals per locus of the population
Hardy-Weinberg equilibrium
p^2 + 2pq + q^2 = 1 (mendelian square)
