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Figure 9.4 PowerPoint Presentation

Figure 9.4

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Figure 9.4

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  1. Figure 9.4 Today we can show the exact location of genes (genotypes) on chromosomes Gene loci Dominantallele a P B Homologouschromosomes b P a Recessiveallele aa Bb PP Genotype: Homozygousfor the recessiveallele Homozygousfor the dominantallele Heterozygous,with one dominantand one recessiveallele

  2. Figure 9.UN01 We can follow the inheritance patterns of these gene location during reproduction Homologouschromosomes Alleles, residingat the same locus Fertilization Meiosis Gametefrom theother parent Diploid zygote(containingpaired alleles) Paired alleles,different formsof a gene Haploid gametes(allele pairs separated)

  3. Figure 9.19B The story of linked genes (two or more genes found on the same chromosome) using fruit flies as a model of genetics

  4. Figure 9.18C-1

  5. Figure 9.18C_2 The Explanation g l G L GgLlFemale ggllMale g l g l Crossing over g l g l G L g L G l Eggs Sperm Offspring g l g L G L G l g l g l g l g l Recombinant Parental

  6. Figure 8.16 What’s true for flies is (often) true for mammals Coat-color genes Eye-color genes E C Brown Black Brown coat (C); black eyes (E) C E C E Meiosis e c c e c e White Pink Tetrad in parent cell (homologous pair of duplicated chromosomes) Chromosomes of the four gametes White coat (c); pink eyes (e)

  7. Figure 8.17B_1 E C Tetrad (pair of homologous chromosomes in synapsis) c e Breakage of homologous chromatids 1 C E c e Joining of homologous chromatids 2 C E Chiasma c e

  8. Figure 8.17B_2 C E Chiasma c e Separation of homologous chromosomes at anaphase I 3 C E C e E c c e

  9. Figure 8.17B_3 C E C e E c c e Separation of chromatids at anaphase II and completion of meiosis 4 C E Parental type of chromosome C e Recombinant chromosome c E Recombinant chromosome c e Parental type of chromosome Gametes of four genetic types

  10. Figure 9.19A Mapping chromosomes Section of chromosome carrying linked genes g c l 17% 9% 9.5% Recombinationfrequencies

  11. Figure 9.20B Sex-determining chromosomes Female Male 44XX 44XY Parents(diploid) 22X 22Y 22X Gametes(haploid) Sperm Egg Offspring(diploid) 44XY 44XX Male Female

  12. Alternate “rules” to determine males One instead of two Homozygous Haploid (no sex chromosomes) Fig. 9-20c

  13. Figure 9.22 Sex-linked diseases are more common in males than females QueenVictoria Albert Alice Louis Female Male CzarNicholas IIof Russia Alexandra Hemophilia Carrier Normal Alexis

  14. Figure 9.21C Female Male XRY XRXr Sperm Y xR XRY XRXR XR Eggs XrXR Xr XrY R red-eye allele r white-eye allele

  15. Figure 9.21B Female Male XrY XRXR Sperm Xr Y XR Eggs XRXr XRY R red-eye allele r white-eye allele

  16. Figure 9.21D Female Male XRXr XrY Sperm Xr Y XRXr XRY XR Eggs Xr XrY XrXr R red-eye allele r white-eye allele