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Genetics Outline with Chapter References for Biology, 7th ed.*
*Figures unless otherwise noted
I.
Molecular Genetics: knowledge that fuels the genetic revolution
A. DNA and DNA replication
1. DNA structure (and RNA structure) (Figures 5.26, 16.5, 16.6, 16.7, 16.8, 16.X-pg. 298)
2. DNA structure provides a mechanism for DNA replication (5.27, 16.9)
3. Steps in DNA replication (16.10, 16.12, 16.13, 16.14, 16.15, 16.16)
4. DNA replication involves many enzymes (gene products): (Table 16.1)
5. DNA replication has special problems at the ends of linear molecules (16.18, 16.19)
(http:web.centre.edu/bmb/movies/Telomeres.html)
B. Mitosis
1. DNA replication produces sister chromatids, which can be sorted into different
daughter cells in the process of mitosis (12.4)
2. DNA replication is part of the cell cycle (12.5)
3. Sister chromatids experience cohesion from the time of their creation
4. Chromatin condenses more tightly at the beginning of mitosis (12.6)
5. Steps in sorting sister chromatids (steps of mitosis) (12.1, 12.6, 12.9, 12.10)
6. Because of DNA replication and mitosis, all cells in a multi-cellular organism have the
same set of DNA (12.2)
7. All cells have the genetic instructions for producing an entirely new individual (21.5,
21.6, 21.7)
C. Meiosis
1. Chromosome number is critically important for proper function (15.1, 15.15)
2. Chromosome number: euploidy, polyploidy, aneuploidy, diploid, haploid, etc.
3. Meiosis allows sexually reproducing organisms to produce haploid gametes (13.5, 13.7,
13.8, 13.9, 46.11, 13.10, 13.11)
4. Non-disjunction in meiosis I or meiosis II creates aneuploid gametes (15.12)
D. DNA organization changes during the cell cycle (12.5, 12.X onion root tip pg. 235)
1. Chromatin condenses more tightly in dividing cells (12.6)
2. DNA is packed with important proteins to create “chromatin” in non-dividing cells
(19.2); chromosome territories
E. Much of our genome is “non-gene”
Exam 1
F. Genes code for RNA products
1. RNA-only genes produce functional RNA’s (tRNA, rRNA, miRNA, and more)
2. Protein-coding genes produce mRNA’s (17.3)
3. Transcription makes an RNA copy of a gene (17.4, 17.7)
4. Transcription begins when transcription factors bind to the promoter of a gene (17.8)
G. Translation is the process of assembling a protein
1. Eukaryotes modify their mRNA in important ways before it can be used in translation
(17.9, 17.10, 17.11, 17.12)
2. Translation uses mRNA as instructions for making a protein (17.3, 17.5, 17.13)
3. Machinery of translation: tRNA’s (17.14), amino acids (17.15, 5.17), mRNA’s, and
ribosomes (17.20)
4. Steps of Translation (17.17, 17.18, 17.19)
5. Transcription and Translation summary: 17.26; DNA sequence determines protein
shape
6. Protein shape determines function (5.20, 18.13)
H. Gene Expression:
1. Characteristics of a cell depend on which genes are expressed within it
2. Tissue-specific gene expression vs. house-keeping genes (pg. 362)
3. Genes are regulated in a variety of ways (19.3)
4. Genes can be regulated by turning on/off transcription
a. Epigenetic factors regulate chromatin structure (heterochromatin and
euchromatin), which determines if transcription is possible
i. DNA (cytosine) methylation (pg. 364); X-chromosome inactivation (15.11)
b. Binding of specialized transcription factors (activators) to proximal and distal
control elements (enhancers) can promote increased transcription levels (19.6,
19.7)
c. Binding of specialized transription factors (repressors) to proximal and distal
control elements can prevent transcription
5. Gene regulation is also possible after transcription
a. Alternative RNA splicing allows multiple proteins to be made from a gene (19.8)
b. mRNA lifespan determines how much translation can occur
i. lifespan may depend on the 3’UTR sequence (19.5)
ii. lifespan may depend on miRNA action (19.9)
II. Gene Expression in Diploid, Multi-Cellular Organisms
A. Many genes show genetic variation in a population (alleles) (14.4)
1. Loss-of-function (LOF) mutations: either no protein produced, or protein is nonfunctional
2. Gain-of-function (GOF) mutations: protein is produced and is functional, but has a
different function than the original protein
B. An individual’s phenotype depends on which alleles they carry and what goes on at the
molecular level for each allele:
1. Homozygous vs. heterozygous
2. The spectrum of dominance (pg. 260):
a. Complete dominance vs. codominance vs. incomplete dominance (14.10)
b. The proper term for two alleles may depend on which phenotypic trait is
considered (pg. 261)
c. Haplo-sufficient vs. haplo-insufficient
3. Many examples: round vs. wrinkled peas, normal vs. LOF p53, Huntington’s Disease,
sickle-cell anemia (5.21), ABO blood types (Table 14.2), color blindness, eye color
C. The laws of probability govern the sorting of alleles into gametes during meiosis, and thus,
the genotype(s) of offspring (14.9)
1. Autosomal genes vs. sex-linked genes (14.5, 15.X-pg. 282, 15.10)
2. The action of each allele at the molecular level
D. Laws of probability may govern how common each genotype is in a population
Exam 2
III. Applied Genetics
A. Cancer occurs when key genes are over-expressed, under-expressed, or mutated
1. Introduction to cancer (12.18)
2. Genetic changes (over-expression or GOF mutations) can turn protooncogenes into
oncogenes (pg. 371, 12.17, 19.11, 19.12a)
3. Tumor-suppressor genes can be under-expressed or have LOF mutations (pg. 371,
12.14, 12.15, 19.12b)
4. Malfunctioning DNA repair genes (LOF mutations or underexpression) can increase the
likelihood of unrepaired mutations in TS genes and protooncogenes
5. Epigenetic changes can contribute to oncogenesis
6. Oncogenesis is a stepwise process, usually involving many cellular and genetic changes
(19.13)
7. Metastasis may involve more mutations than does oncogenesis (12.19)
8. Changes in DNA sequence (mutations) can contribute to oncogenesis (19.11)
a. Some mutations are spontaneous
i. Nondisjunction can increase the number of copies of a gene
ii. DNA polymerase errors change the DNA sequence (17.22)
iii. Breaks in chromosomes during DNA replication Gene amplification
b. Some mutations are induced
i. Radiation, UV light, chemicals, free radicals
B. Genetic technologies rely on manipulating DNA
1. Tools used in genetic engineering (20.3)
2. Gene cloning (20.2, 20.4, and 20.6a)
3. GMO’s (20.18 and 20.19) and gene therapy (20.16)
4. DNA fingerprinting
5. Reproductive cloning and therapeutic cloning (each depends on epigenetic
reprogramming)
Exam 3
IV. Population Genetics
A. What is a “species” (24.4)? What is a “population” (23.3)?
B. Populations within a species differ genetically (23.3, 23.10, 24.3b)
C. Populations change genetically over time. Effects of:
1. Mutation (23.6)
2. Migration
3. Non-random mating
4. Genetic drift (23.7, 23.8)
5. Natural selection on populations (23.12, 23.13)
D. Hardy-Weinberg genotype proportions
E. Genetic change over time can lead to reproductive isolating mechanisms (speciation) (24.2,
24.4, 24.5, 24.6, 24.7)
Exam 4
Lab Techniques:
Lab 3: PCR: (20.7)
Lab 4: Sequencing: (20.12)
Lab 9: Karyotyping: (13.3, 14.17)