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Genetics review. Chapters 12-15. Mitosis . Why mitosis? Homologous chromosomes Chromatids Haploid Diploid Binary fission Tumor Metastasis. 0.5 µm. Chromosomes. DNA molecules. Chromo- some arm. Chromosome duplication (including DNA synthesis). Fig. 12-4. Centromere. Sister
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Genetics review Chapters 12-15
Mitosis • Why mitosis? • Homologous chromosomes • Chromatids • Haploid • Diploid • Binary fission • Tumor • Metastasis
0.5 µm Chromosomes DNA molecules Chromo- some arm Chromosome duplication (including DNA synthesis) Fig. 12-4 Centromere Sister chromatids Separation of sister chromatids Centromere Sister chromatids
Fig. 12-5 INTERPHASE S (DNA synthesis) G1 Cytokinesis G2 Mitosis MITOTIC (M) PHASE
G1 S Fig. 12-17b Cdk Cyclin accumulation M G2 Degraded cyclin G2 checkpoint Cdk Cyclin is degraded Cyclin MPF (b) Molecular mechanisms that help regulate the cell cycle
Meiosis • Genetic variation • Chiasmata • Synapsis
Mendel genetics • Homozygous • Heterozygous • Parental, F1, F2 • Genotype • Phenotype • Testcross • Monohybrid • Dihybrid
Mendel • Law of segregation • Law of independent assortment • Incomplete dominance • Codominance • Multiple alleles • Epistasis • Pleiotropy • Polygenes • Dominant disorders
Fig. 15-2 P Generation Yellow-round seeds (YYRR) Green-wrinkled seeds (yyrr) y Y r R r R Y y Meiosis Fertilization r y Y R Gametes All F1 plants produce yellow-round seeds (YyRr) F1 Generation R R y y r r Y Y LAW OF SEGREGATION The two alleles for each gene separate during gamete formation. LAW OF INDEPENDENT ASSORTMENT Alleles of genes on nonhomologous chromosomes assort independently during gamete formation. Meiosis r r R R Metaphase I y Y y Y 1 1 r r R R Anaphase I Y y Y y Metaphase II r R R r 2 2 y Y y Y y Y Y y Y y y Y Gametes r R r r R r R R 1/4 1/4 1/4 1/4 yr yR YR Yr F2 Generation An F1 F1 cross-fertilization 3 3 : 1 : 3 9 : 3
Sex linked • Hemophilia • Color blindness • Duchene’s muscular dystrophy
Fig. 15-4 EXPERIMENT P Generation F1 All offspring had red eyes Generation RESULTS F2 Generation CONCLUSION + P w w X X Generation X Y + w w Sperm Eggs + + F1 w w + Generation w w + w Sperm Eggs + + w w + F2 w Generation + w w w w + w
Linked genes • Genes on same chromosome • Testcross more parental types
Fig. 15-10 Testcross parents Gray body, normal wings (F1 dihybrid) Black body, vestigial wings (double mutant) bvg b+vg+ bvg b vg Replication of chromo- somes Replication of chromo- somes b+vg+ bvg b+vg+ bvg bvg bvg bvg bvg Meiosis I b+vg+ Meiosis I and II b+vg bvg+ bvg Meiosis II Recombinant chromosomes bvg bvg+ b+vg b+vg+ Eggs Testcross offspring 965 Wild type (gray-normal) 944 Black- vestigial 206 Gray- vestigial 185 Black- normal bvg b+vg+ bvg b+vg bvg+ bvg bvg bvg bvg Sperm Parental-type offspring Recombinant offspring 391 recombinants Recombination frequency 100 = 17% = 2,300 total offspring
Human disorders • Aneuploidy • Nondisjunction • Down syndrome • Klinefelter’s syndrome • Turner syndrome • Philadelphia chromosome • Deletion, duplication, inversion, translation