• wealthy
• got invited to go on voyage of Beagle (1831-6)
• was supposed to captain's gentleman companion

• adaptation
• differential reproduction according to phenotype
• fossil record

1. Pattern - evolutions occurs, common descent. (Uniformitarianism, using current processes to explain past events, was helpful to Darwin)
2. Process - natural selection

1. Anatomical
2. Vestigial (i.e. human tailbone)
3. Developmental (ie gill pouch in embryo of vertebrates
4. Molecular (coding gene, non-coding regions) 

• struggle for existence
• Darwin alarmed by Malthus' idea
• why do some organisms end up reproducing, but not others? 

1. Individuals w/in a population must vary
2. Some of these variations must be heritable
3. Not all individuals will survive to reproduce (Differential Reproduction)
4. If (and only if) 1-3 are true, favorable traits increase in the next generation

• Natural selection is NOT survival of the fittest (that is not very descriptive)
• nat. selection is NOT for 'the good of the species'.. acts at level of individual

• Darwin's finches
• Tuberculosis - antibiotic resistance

1. sex: egg and sperm unite (fertilization)
2. nuclei fuse
3. egg and sperm are gametes(reproductive cells)
4. genetic material in gametes created via meiosis

1. Role = sexual reproduction
2. Ploidy of products =N (half of parent)
3. # cell divisions = 2
4. Chroms. identical to parents? NO
5. Synapsis of homologs? YES

They have the same genes, in the same location, but the genes have different versions (not like in sister chromatids that are exact replicas)

1. Role = growth
2. Ploidy of products = 2N (same as parents)
3. # cell divisions =1
4. Chroms. identical to parents? yes
5. Synapsis of homologs? no

• N =23
• 2N =46

• carry genes that determine sex

1. Independent Assortment
2. Recombination due to crossing over
3. Different possibilities of mates

• Nondisjunction: uneven distribution of chroms
• Polyploidy results from nondisjunction of all chroms
• Seedless watermelon comes from 4N  x  2N-->3N
• mule
• [image]

• "pure lines" - reliably produce progeny like parents
• often called inbred or isogenic
• Mendel worked with pure lines of garden peas

• Compares only 1 trait
• parents both homozygous
• F1 = heterozygous, all same phenotype (self these)
• F2 = 3:1 ration of phenotypes

• Separation of two alleles of parents into gametes
• "particulate inheritance"
• Alleles transferred across generation separately in gametes)

1. Alternative versions of genes account for variations in inherited characteristics. This is the concept of alleles. Alleles are different versions of genes that impart the same characteristic. For example, each human has a gene that controls eye color, but there are variations among these genes in accordance with the specific color for which the gene "codes".
2. For each characteristic, an organism inherits two alleles, one from each parent. This means that when somatic cells are produced from two alleles, one allele comes from the mother and one from the father. These alleles may be the same (true-breeding organisms/homozygous e.g. ww and rr in Fig. 3), or different (hybrids/heterozygous, e.g. wr in Fig. 3).
3. The two alleles for each characteristic segregate during gamete production. This means that each gamete will contain only one allele for each gene. This allows the maternal and paternal alleles to be combined in the offspring, ensuring variation.

• A dihybrid cross is a cross between two individuals that differ in two traits. For example: RRyy/rrYY or RRYY/rryy.

• A dihybrid cross is often used to test for dominant and recessive genes in two separate characteristics.

• Dihybrid crosses yield 9:3:3:1 phenotype ratio

• loci = plural
• at each locus, 2 alleles 

• = gene
• Dominant, recessive,
• incomplete=heterozygote has intermediate phenotype (i.e. one purple parent, one white gives lavender kids)
• codominance=both alleles are expressed (both purple and white)
• Multiple alleles at a locus (i.e. ADH alcohol dehydrogenase alleles in human pop)

• usually attached to X
• if so, men more likely to get than women

• Codominant: A and B
• Recessive: i
• Dominant: A and B over i 

• Due to interactions among alleles at more than one locus affecting a trait
• Locus 1: Color (C) dom to albino (c)
• Locus 2: Black (B) dom to brown (b)
• [image]
• genotype = 9:3:3:1
• Phenotype = 9:3:4

• Shape
• size
• metabolic rates
• physiological rates
• BELL-SHAPED CURVE

• Alleles at each locus contribute to trait
• Comples diseases influenced by multiple genes in interaction w/ the environment
  • Diabetes
  • cancer
  • alzheimer's
  • schizophrenia
  • epilepsy

• Enzyme that cuts DNA at a specific sequence
• made by bacteria
• Bacteria safe though because their DNA is methylated (CH3 group) at these sites
  • (they won't accidentally cut themselves apart)

• early form of genetic marker
• Restriction enzymes will cut DNA into diff. length fragments, revealing genetic variation
  • cut up DNA
  • run out on gel
  • visualize certain fragments using radioactive probe (probe=SS DNA complementary to part of sequence) 

• make many copies of certain strands DNA
• If use messnger RNA, will clone DNA that is expressed in a certain tissue
• If clone into 'expression vector' can make gene product
• can also cloe 'genomic DNA' which will include non-coding regions
• Need MANY copies of a fragment of DNA to study it
• Cloning is using bacteria to make many copies
  • mRNA-->cDNA
    • put into plasmid that can go into bacteria

• Efficient way to make copies of a piece of DNA
• Has replaced cloning for some applications
• Need
  • DS DNA (the template)
  • primers
  • DNA polymerase
  • dNTPs (bases A, C, T, G)
  • buffer to run reaction in

• Repeats 3 steps:
  • Denaturation @ 94 deg (to separate strands to get ss DNA)
  • Primer annealing @ 64 deg (to the template by complementary base pairing)
  • Extension @ 72 deg (polymerase uses dNTPs to synthesize complementary DNA, starting at primer)

• At each repetition, the number of copies of DNA doubles