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Chapters 15, 16, 17: Mendelian Genetics (2) - Coggle Diagram

- - - - Filial (F1 generation): observe phenotype in the resulting seed or the plants produced by these seed (same plants, different developmental stages)
- - - - F1 generation: All plants had purple flowers (purple allele is dominant)
        
        F2 generation: 3 purple flowers, 1 white flower (shows that genes are stable: the white allele is inherited unchanged)
        
        INTERPRET 3:1 SEGREGATION RATIO: Individuals have 2 copies of every gene, but their gametes only have 1
        
        Pgen: PP x pp --> gametes: P x p --> F1gen: Pp --> gametes: 1/2P 1/2p --> F2gen: PP, Pp, Pp, pp: 3:1 ratio
        
        Genes controlling the same trait segregate from one another during gamete transformation --> gametes unite randomly during fertilization --> frequency of different phenotypes is determined by combinatorial interactions between gametes of 2 different states
  - - - Alleles segregate during Meiosis
        
        Meiosis I: Homologous chromosomes separate (purple allele chromosome goes to one cell, white allele chromosome goes to another cell)
        
        Meiosis II: Sister chromatids separate --> go to gametes
- - - - 9:3:3:1 (dominant for both traits: recessive for trait 1: recessive for trait 2: recessive for both traits)
- - - - Missense mutations at different places on the tyrosinase gene: aa is changed from one to something else --> can have different phenotypes
        
        wild type: dark
        
        albino: null allele
        
        His-->Arg (even though both aa are polar, the backbone of Arg is much bigger than His)
        
        chinchilla: weak allele
        
        Ala --> Thr (changes from polar-->nonpolar but protein still retains some activity)
      - Siamese cats: temperature sensitive mutation of tyrosinase (conditional)
        
        when it's WARM --> the temperature-sensitive mutation INACTIVATES tyrosinase protein --> albino
        
        cats are albino in warmer body region, dark in cooler body regions
- - - - ex. ASP controls distribution of black pigment
        
        mutate a mouse to overexpress Agouti --> yellow, obese, infertile, susceptible to tumors