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Unformatted text preview: 38 Chapter 2 • Patterns of Inheritance equal segregation and independent assortment, we can predict that as we have just demonstrated by using the Punnett square. He reasoned that, if there were in fact a 1:1:1:1 ratio of R ; Y , R ; y , r ; Y , and r ; y gametes, then, if he crossed the F 1 dihybrid with a plant of geno- type r / r ; y / y , which produces only gametes with re- cessive alleles (genotype r ; y ), the progeny propor- tions of this cross should be a direct manifestation of Multiplication along the branches gives us the gamete proportions: These proportions are a direct result of the application of the two Mendelian laws. However, we still have not arrived at the 9:3:3:1 ratio. The next step is to recog- nize that both the male and the female gametes will show the same proportions just given, because Mendel did not specify different rules for male and female gamete formation. The four female gametic types will be fertilized randomly by the four male gametic types to obtain the F...
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This note was uploaded on 01/10/2011 for the course BIOL BIOL taught by Professor Johnson during the Spring '08 term at Aberystwyth University.
- Spring '08