The diagram represents a dihybrid cross between two pea plants heterozygous for both seed color and seed shape. mc021-1.jpg What
is the phenotypic ratio of the offspring? 1:1:1:1:2:2:2:2:4 1:3:3:9 1:4 4:12
2 answers:
The correct answer is 9:3:3:1
When two homozygotes for two traits cross, the phenotypic ratio of the offspring is 9:3:3:1 ( unless other factors like epistatic interaction change the inheritance model).
In our case, we have two simple traits of seed color and seed shape that follow the Mendelian model of inheritance.
In this dihybrid cross, we have
9/16 of the offspring expressing both dominant traits ( yellow and round seeds)
3/16 expressing one dominant and one recessive trait ( yellow and wrinkled)
3/16 expressing the other dominant and recessive trait (green and round)
1/16 expressing both recessive traits ( green and wrinkled)
When two homozygotes for two traits cross, the phenotypic ratio of the offspring is 9:3:3:1 ( unless other factors like epistatic interaction change the inheritance model).
In our case, we have two simple traits of seed color and seed shape that follow the Mendelian model of inheritance.
In this dihybrid cross, we have
9/16 of the offspring expressing both dominant traits ( yellow and round seeds)
3/16 expressing one dominant and one recessive trait ( yellow and wrinkled)
3/16 expressing the other dominant and recessive trait (green and round)
1/16 expressing both recessive traits ( green and wrinkled)
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