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TLS Online TPP Program

#Question id: 13143

The Norway rat (Rattus Norvegicus), a widespread pest, was controlled for about a decade by the anticoagulant warfarin. This chemical substance, placed in food pellets, is absorbed by the intestinal tract and inhibits the clotting of blood. After a population decline for about 10 years, rat populations increased and stabilized. In one European population, as illustrated in the graph below, the percentage of rats resistant to warfarin has remained fairly stable over a number of years.

Resistance to warfarin is governed by a dominant autosomal gene, R. More than 15 percent of the resistant animals are heterozygous at this locus (Rr). The table below indicates the response to warfarin and relative reproductive fitness of individuals that are homozygous or heterozygous for the dominant gene (R). The RR individuals have a 20-fold increase in vitamin K requirement over individuals.

Fitness is a measure of the reproductive success of a particular genotype. The highest fitness is 1.00.
In a population where warfarin is no longer applied, the expectation is that the

#Unit 10. Ecological Principles
  1. Dominant gene (R) will supplant the recessive gene (r) in the population
  2. Heterozygotes (Rr) will have a reproductive advantage over both homozygotes (RR and rr) 
  3. Frequency of the dominant gene (R) will decline
  4. Frequency of recessive individuals will gradually decline
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TLS Online TPP Program

#Question id: 23693

#Unit 13. Methods in Biology

the DNA fragments making up a genomic library are generally contained in
TLS Online TPP Program

#Question id: 12574

#Unit 10. Ecological Principles

According to the small- population approach, what would be the best strategy for saving a population that is in an extinction vortex?
TLS Online TPP Program

#Question id: 23884

#Unit 13. Methods in Biology

Expression of a cloned eukaryotic gene in a bacterial cell involves many challenges. The use of mRNA and reverse transcriptase is part of a strategy to solve the problem of
TLS Online TPP Program

#Question id: 14999

#Unit 8. Inheritance Biology

I know that black coat color in mice is dominant to albino. Black mice get a higher price at the pet store so I am disappointed when I cross a black mouse with an albino mouse and get 6 albino and 2 black mice in the litter. I expected all black. What mistake did I make?