Help me out a little with some biology!?

Can someone show me in detail how to answer this? If you know the answer, please show me the steps on how to do this. Thank you.





An individual with genotype Tt is crossed with another individual with genotype Tt. The mode of inheritance is autosomal dominant.


What fraction of the offspring is expected to exhibit the recessive trait? (Select one)





A. none


B. one-fourth


C. One-Half


D. Three-Fourths


E. All

Help me out a little with some biology!?
ehxhibit means to be able to see it in the organism. based on the laws of probability and chance 1/4 or 25% of the possible offspring may exhibit the trait.





Tt X Tt








T t


T TT Tt





t Tt tt
Reply:The answer is B





When you cross two heterozygous parents you always get 1/4 -dominant


1/4-recessive


2/4-heterozygous
Reply:TT = NO = 25%


Tt = YES = 50%


tt = YES = 25%





75% or D
Reply:The answer is 1/4.





The recessive trait is, by definition, recessive, and you won't see it in heterozygous individuals. (If you did, then it would be completely dominant, and the other trait woud be recessive).





So in a hybrid cross, you have a 1:2:1 ration of homozygotes, hets/homozygotes. Only those homozygous for the recessive allele will show the recessive phenotype, and that's 1/4th the offspring.

survey monkey