Its in your Genetics Genetic Vocabulary Allele Dominant

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 F 1 generation, results were all dominant phenotype (heterozygous) • F 1 generation self pollinated and produced the F 2 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… • Yy. Rr x Yy. Rr = 9: 3: 3: 1 • YYRR x anything is always 100% dominant • Yy. Rr x yyrr = 1: 1: 1: 1 • Figure 11. 8, page 212 • Trihybrid anyone? ?