Answers%20to%20Questions%20posed%20in%20Lecture%2019

Answers%20to%20Questions%20posed%20in%20Lecture%2019 -...

Info iconThis preview shows pages 1–7. Sign up to view the full content.

View Full Document Right Arrow Icon
Answers to Questions posed in Lecture 19
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
How is variation maintained if natural selection is operating? spatial (conditions differ from place to place) and temporal variation (conditions vary from time to time in seasons or years) creates conditions where different forms are favored so that many types persist; sexual reproduction and crossing over also continuously shuffle the genetic deck and create new genetic combinations
Background image of page 2
You are hired by Insects-R-US to study cockroaches. They have a good insecticide, but a few cockroaches can eat it and live. These roaches carry the T allele. Your job is to estimate allele frequencies after a few generations of exposure to insecticide. You sample roaches and find these genotype frequencies: f (TT) = 0.05: f (Tt) = 0.50; f (tt) = 0.45 • What is the frequency of the T allele in the population: •A . 0 . 1 0 •B . 0 . 2 0 C. 0.30 • D. 0.40 •E . 0 . 5 0 f(T) = 2 x N x 0.05 + 1 x N x 0.50 / 2N = 0.60/2 = 0.30
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
What are the expected frequencies of the 3 genotypes under conditions of Hardy- Weinberg equilibrium? •A . f (TT) = 0.05: f (Tt) = 0.50; f (tt) = 0.45 •B . f (TT) = 0.90: f (Tt) = 0.05; f (tt) = 0.05 •C . f (TT) = 0.09: f (Tt) = 0.21; f (tt) = 0.70 D. f (TT) = 0.09: f (Tt) = 0.42; f (tt) = 0.49
Background image of page 4
Compare your observed and expected values (>.02 apart = different). Which of the following is true? D. f (TT) = 0.09: f (Tt) = 0.42; f (tt) = 0.49 OBS: f (TT) = 0.05: f (Tt) = 0.50; f (tt) = 0.45 A. there are fewer TT animals than expected •B . there is a deficiency of heterozygotes •C . there are more tt animals than expected •D . the observed values match expected •E . the population is in H-W equilibrium
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
You know that animals with the T allele can eat the pesticide and survive. Do your results fit in well with this knowledge? No, there should be more of this type and there
Background image of page 6
Image of page 7
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 18

Answers%20to%20Questions%20posed%20in%20Lecture%2019 -...

This preview shows document pages 1 - 7. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online