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Chapter 10 Figure 10.1a Self-pollination SELF-POLLINATION Stigma (receives pollen) Anthers (produce pollen grains, which contain male gametes) Ovules (produce female gametes) Figure 10.1b CROSS-POLLINATION 1. Remove anthers from one plant. 2. Collect pollen from a different plant. 3. Transfer pollen to a stigma of the individual whose anthers have been removed. Figure 10.2 upper Phenotypes Trait Seed shape Round Wrinkled Yellow Green Seed color Pod shape Inflated Constructed Pod color Green Yellow Figure 10.2 lower Phenotypes Trait Flower color Purple White Axial (on stem) Terminal (at tip) Flower and pod position Stem length Tall Dwarf Figure 10.3a First half of reciprocal cross …to stigma of wrinkled-seeded parent Pollen from roundseeded parent… All progeny have round seeds Figure 10.3b Second half of reciprocal cross Round-seeded parent receives pollen... All progeny have round seeds …from wrinkledseeded parent Results of second generation crosses Mendel found that the recessive traits reappeared in some individuals He found 14,949 plants in his second generation with the dominant trait and 5,010 with the recessive trait This ratio of 2.98 to 1 suggests a threeto-one ratio Figure 10.7 R = Dominant allele for seed shape (round) r = Recessive allele for seed shape (wrinkled) = Round-seeded phenotype = Wrinkled-seeded phenotype Mother Rr Female gametes Father Rr Male gametes R r R RR Rr Rr rr r Resulting genotypes: 1/4 RR : 1/2 Rr : 1/4 rr Resulting phenotypes: 3/4 : 1/4 Chapter 9 Meiosis is a Special Type of Cell Division that Occurs in Sexually Reproducing Organisms Meiosis reduces the chromosome number by half, enabling sexual recombination to occur. Meiosis of diploid cells produces haploid daughter cells, which may function as gametes. Figure 9.2a Each chromosome replicates prior to undergoing meiosis. Paternal chromosome Maternal chromosome Duplication Sister chromatids Centromere Homologous pair of premeiotic chromosomes Figure 9.2b Parent cell contains homologous pair of chromosomes Homologs separate Sister chromatids separate Four daughter cells contain one chromosome each. These cells become gametes. Daughter cells contain just one homolog MEIOSIS II MEIOSIS I During meiosis, chromosome number in each cell is reduced. Figure 9.2c A full complement of chromosomes is restored during fertilization. Female gamete Male gamete Fertilization Diploid offspring contains homologous pair of chromosomes Figure 10.7 R = Dominant allele for seed shape (round) r = Recessive allele for seed shape (wrinkled) = Round-seeded phenotype = Wrinkled-seeded phenotype Mother Rr Female gametes Father Rr Male gametes R r R RR Rr Rr rr r Resulting genotypes: 1/4 RR : 1/2 Rr : 1/4 rr Resulting phenotypes: 3/4 : 1/4
