Exam 1 Review
9:50 AM
Youtube Notes:
• Dihybrid cross: First Outer Inner Last. FOIL each parent
○ P->F1: YYRR -> YR, yyrr ->yr
F1: YyRr
○ F1->F2: YyRr x YyRr FOIL
YR, Yr, yR, yr
F2 Ratio -> 9:3:3:1
• Incomplete dominance -
• Codominance -
Chapter 1 Quiz Questions:
• Central dogma: DNA -> RNA -> protein
• Modern synthesis - merges evolutionary theory with experimental mathematical, and molecular
population biology.
• Watson and Crick - proposed accepted model for the structure of DNA
• What evolutionary process can lead to genetic change in the populations/evolution?
○ Mutation, genetic drift, migration, and natural selection
• Genetics is the science of heredity and variation
• To what strand end is the next nucleotide added during nucleic acid synthesis? 3' end
• Mutation is the ultimate source of genetic variation
• Pleiotropic - Mutation caused by a single gene, but symptoms vary and affect different organs.
• Both DNA and RNA have a sugar-phosphate bond, are attached via phosphodiester bond and have
a sugar attached to a nitrogenous base
• Natural selection is the only evolutionary process that leads to the adaptation of organisms to
their environment.
Chapter 2 Quiz Questions:
• In flies, several genes are involved in eye color. For the brown gene, individuals carry at least one
dominant allele, B, show wild type, dark red eyes and brown eyes are observed in individuals bb,
homozygous for the recessive allele. You are given the following phenotypic counts of the progeny
from a cross: 140 flies with red eyes and 138 flies with brown eyes. Determine the genotypes of
the parents of this cross: Bb x bb
• Genetic traits can skip a generation
• A pea plant heterozygous for pod shape and pod color was selfed. The progeny consisted of 315
round and yellow pods, 108 round green, 101 wrinkled yellow, 32 wrinkled and green pods. For
both traits there is a dominant allele and recessive allele. You would like to perform a chi-square
test to see if the observations fit the expectation of mendel's laws. What would be the critical
value of the chi square distribution you will compare your X^2 value with? Df = 4(phenotypes)-1
=3, p value = 0.05
Genetics Page 1
, • Five unlinked genes: qq, Rr, Gg, PP, mm. Suppose and infinite number of gametes are formed by
this individual. What is the proportion of gametes that will have the genotype qrPGm? 25%
mm, gg, PP all homozygous, do not affect genotype. Rr x Gg = RG, Rg, rG, rg. rG = 1/4
• Mendel infered
○ No blending inheritance
○ Diploid orgs carry two copies
○ Some traits are dom/recessive
○ Law of segregation - Alleles segregate during the formation of gametes and then come back
together during fertilization, producing random combos
○ Law of independent assortment - during formation of gametes, segregation of alleles at one
locus is independent of segregation of alleles at another locus
• Aa Bb Mm x Aa Bb Mm, probability of all dominant phenotypes - 27/4
○ (3/4 prob to be dom pheno, ^ 3rd for three types
• Binomial prob
Genetics Page 2
