Table 9.2. Kernel texture data. 229 P generation: SS x ss F, generation: Ss x Ss
ID: 3164356 • Letter: T
Question
Table 9.2. Kernel texture data. 229 P generation: SS x ss F, generation: Ss x Ss Expected # of Expected Frequency 3/4 1/4 F Phenotype Observed # of Kernels Observed Frequency smooth wrinkled Total # of kernels 100 Which allele is dominant: smooth kernel or wrinkled kernel? Smoai For a trait for which an ear of corn shows a dominant phenotype, how could you determine if the genotype is homozygous or heterozygous? (Give a de- scription of the experiment.) Did you observe an exact 3:1 ratio in the F, from the kernel texture genetic In your opinion, was the observed ratio cross? "close enough" to a 3:1 ratio for you to conclude that smooth kernel texture is completely dominant over wrinkled kernel texture? Why would using a compilation of class data be more desirable than using your individual data in the evaluation of your hypotheses concerning seed color and kernel texture inheritance?Explanation / Answer
Answer:
Accoding to the observations of the experiment, It says Smooth kernel is a dominant trait.
Dominant phenotype = Smooth kernels
Genotype for the dominant trait could be SS or Ss.
In order to determine the genotype, a test cross in conducted. For a test cross, Genotype for a trait is crossed and checked with the homozygous recessive genotype. F1 generation (now acting as one of the parents in cross) is crossed with the homozygous recessive parent
Case-1:
When F1 generation Ss (heterozygous, dominant) is crossed with ss (homozygous, recessive)
Case-2:
When F1 generation SS ( homozygous, dominant) is crossed with ss (homozygous, recessive)
So, if F1 generation has Ss genotype, then the progenies after test cross with be 50% dominant and 50% recessive. But, if F1 generation has SS genotype, then all the progenies after test cross will show dominant trait.
According to the observations of the experiment, there are 77 smooth kernel that means they show dominant trait and 23 wrinkled kernels that means they show recessive trait.
Thus, genotype of the dominant trait obtained in F1 generation HAS TO BE Ss. beacause, then only recessive traits will be obtained. Had it been SS genotype, all the progenies will be dominant and no recessive trait will occur; which is not a case here. In the experiement we are having some number of recessive trait also that is only possible when the F1 generation (acting as parent in test cross) will have Ss (heterozygous) genotype.
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