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Unformatted text preview: ey assort independently. From Punnett Squares to Probabilities
• If an event is certain to happen, probability = 1
• If an event cannot possibly happen, probability = 0
• All other events have a probability between 0 and 1
• So, for SS homozygotes, the probability that a gamete will carry S = 1 • And for ss homozygotes, the probability that a gamete will carry the s allele = 1 • For an Ss heterozygote, the probability that a gamete will carry an... • S allele = 1/2 (0.5) • s allele = 1/2 (0.5) Using probabilities instead of Punnett Squares
Gamete from parent 1 Gamete from parent 2 Some Simple Rules of Probability Theory
The Multiplication Rule:
• Probability of two independent events happening together: multiply the
probabilities of the individual events.
• Tossing two coins: probability that both will come up heads:
• ½ x ½ = ¼ • In the F2’s, there is 1 way to get an SS offspring (½ x ½ = ¼) & 1 way to
get an ss offspring (½ x ½ = ¼).
Ø། That is, you have two “draw” 2 Salleles in a ro...
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This document was uploaded on 02/19/2014.
 Fall '14

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