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Hand in Genetics Problems Worksheet before the bell rings please Review Chapter 8 Quiz 1 Chapter 8 – Beyond Mendel Review Dihybrid crosses Chapter 8 Quiz 2 Preview Probability Test Crosses Pedigree “The man who does not read good books has no advantage over the man who cannot read them.”
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Hand in Genetics Problems Worksheet before the bell rings please Review Chapter 8 Quiz 1 Chapter 8 – Beyond Mendel Review Dihybrid crosses Chapter 8 Quiz 2 Preview Probability Test Crosses Pedigree “The man who does not read good books has no advantage over the man who cannot read them.” Mark Twain To continue learning about Mendelian genetics and learn about some of the aberrations to Mendelian genetics Title: Biology 2/5/07 Class Topics Objectives: Wednesday, January 1, 202010:31 PM
Class Assignments What By When • Genetics Problems 2/5/07 • Read 170-178 2/5/07 • Chapter 8 Quiz 2 2/7/07 • W.S. Probability and dihybrid crosses 2/7/07 • Due this class period • Due next class period • Due in the future
Grade Sheet 2A – p. 157 (5 pts.)
Dihybrid Cross • GgTt x GgTt
Results • F1 - Pheno • Green/Tall • Green/short • yellow/Tall • yellow/short • What if there were 961 of these seeds planted? Approximately, how many of each type would there be?
Probability • Likelihood that an event will occur • Expressed as a fraction, ratio, decimal, or percentage (we’ll use fractions) • Probability of a coin landing as “heads”? • 1:1, ½, 0.50, 50% • Probability a heterozygote will produce a dominant allele in its gamete?
Probability • Product rule • Toss a coin – probability of “tails”? • ½ • Toss the same coin again – probability of “tails”? • ½ • Probability of 2 “tails” • ½ x ½ = ¼
Probability • Male • 1/2 • Female • 1/2 • Family with having a boy, a girl, a boy, and a girl in that order.
Test Cross • Used when there’s an unknown genotype of dominant phenotype • Crossed with a homozygous recessive • Recessive phenotype • If offspring are all dominant? • If offspring are ½ dominant and ½ recessive
Test Cross problem • Determine the genotype of a pea plant with yellow seeds if the test cross offspring all have yellow seeds • P ___ x ___ • F1 • Pheno • Geno • What if the F1 had ½ yellow and ½ green seeds?
Chapter 8 Quiz 2 Review • Codominance cross • F1 and F2 generations • Incomplete dominance cross • F1 only • Mendel’s numbers – ratios – pod color • Dihybrid cross 1 • F1 and extrapolate data for more seeds • Dihybrid cross 2 • F1 and F2 generations and extrapolate data for more seeds
Pedigree AnalysisHemophilia • Males = Square • Females = Circles • Each generation is a line • Vertical lines connect parents and children • Indirect horizontal lines connect siblings • Left to right in order with age.
Seen in every generation Skips generations Pedigree Analysis From: http://www.ndsu.nodak.edu/instruct/mcclean/plsc431/mendel/mendel9.htm