It’s in your Genetics!

Genetic Vocabulary Allele Dominant Recessive Homozygous dominant Heterozygous Homozygous recessive Genotype Phenotype Punnett square

Gregor Mendel Austrian Monk Experiment using Pea Plants Fast growing generations Could self pollinate Many offspring at a time Contrasting traits (this was luck)

Mendel’s experiment Took true breeding (homozygous) parents and called them the P generation Allowed them to breed and resulted in the F1 generation, results were all dominant phenotype (heterozygous) F1 generation self pollinated and produced the F2 generation = 3:1 phenotypic ratio

Mendel’s law of segregation Two alleles for a heritable character segregate (separate from each other) during gamete formation and end up in different gametes.

Punnett Square Monohybrid dihybrid

Testcross Used to determine the unknown genotype of an dominant phenotype… Always cross unknown genotype with homozygous recessive If any offspring are recessive, unknown genotype is heterozygous If all offspring are dominant, it is assumed the unknown genotype is homozygous dominant.

11.2 Probability Outcome of any particular toss is unaffected by what has happened on previous trials. What is the chance that two coins tossed simultaneously will both land heads up? Multiplication rule: multiple the probability of one event (heads) by the probability of the other event (heads) = ½ X ½ = ¼ Addition rule: the probability that any one of two or more naturally exclusive events will occur is calculated by adding their individual probabilities ¼ + ¼ = ½

Solving Dihybrid’s with probability First, 3 answers you should always know… YyRr x YyRr = 9:3:3:1 YYRR x anything is always 100% dominant YyRr x yyrr = 1:1:1:1 Figure 11.8, page 212 Trihybrid anyone??