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Dihybrid Crosses. Looking at factors two at a time. Dihybrid Gametes (Two factors). The hybrid (GgYy) can produce GY, Gy, gY and gy GGYy would give the two gametes GY and Gy. Dihybrid cross.
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Dihybrid Crosses • Looking at factors two at a time.
Dihybrid Gametes (Two factors) • The hybrid (GgYy) can produce GY, Gy, gY and gy • GGYy would give the two gametes GY and Gy.
Dihybrid cross • Because of independent assortment, the traits can separate from each other and be inherited independently. • Dihybrid crosses use the 16 square punnett square to show all of the possible combinations.
A heterozygous dihybrid cross. • There are 9 genotypes possible. • There are 4 phenotypes possible.
Genotypic and Phenotypic ratios for Dihybrid crosses • Genotypic ratio order • BBSS:BBSs:BBss:BbSS:BbSs:Bbss: bbSS:bbSs:bbss • Classic 1:2:1:2:4:2:1:2:1 • Phenotypic ratio order • Dom,Dom:Dom,Rec:Rec,Dom:Rec,Rec • Classic 9:3:3:1
Dihybrids have shortcuts!!!! Only Gametes are FY and Fy. Mate FFYy x FfYY FY FY Fy Fy FY FFYY → FFYy → FY → Only gametes are FY and fY → → → fY FfYY → → FfYy fY → → → → Genotypic ratio 4:4:0:4:4:0:0:0:0 Phenotypic ratio 16:0:0:0