Question

Arabidopsis thaliana, a plant, has small leaf projections called trichomes. A search for mutants revealed two mutant strains, A and B, both of which lack trichomes. Strain A plant was propagated until it was completely true-breeding and then crossed to a true-breeding wild-type plant. The F1 was all wild-type. The F2 results are below. The plant geneticist was unable to form a true-breeding plant from strain B plant. When a strain B mutant was crossed to wild-type, the F1 data from mutant B are shown below. For the F2 (results below), a mutant B strain F1 plant was mated to another mutant strain B F1 plant: F2 from mutant A: 602 normal trichomes, 198 trichomes absent F1 from mutant B: 401 normal trichomes, 397 trichomes absent F2 from mutant B: 146 normal trichomes, 304 trichomes absent The mutant allele in A is most likely O autosomal dominant O autosomal dominant, homozygous lethal O autosomal recessive O autosomal recessive, heterozygous lethal It cannot be determined from the information provided. QUESTION 22 The mutant allele in B is most likely O autosomal dominant O autosomal dominant, homozygous lethal o autosomal recessive

Answer 1

Ans: The answer is explained in the image enclosed below:

Als - As in the we are getting all wild Cure and in F2 we mutant type). So from all this given with weld type (frue breading) questreou that the true breeding metant for A uchen crossed type getting 602 normal trichomes and 198 trichomes absent. So this ratio approximately equal to 3:1 (wild type: we can conclude that mutant is active when present in recessive homozygous form @ the mulant A is most likely to be autosomal recessure Coption C). 6 Nove true Nous true foreding of strais B is not formed and when thee esosed with true wild type get 1:1 rato at F1 generation and in Fe Generation mulant strain dominates. So this means that strain B which is crossed firstly veas heterozygous and therefore A generatori Bb (mulant B strain) (wild type) Chameley B6 b que we are getting Id rates in b b F1 Bb bb (1:1 ratio) 80 the mutant allele B is most likely to be autosomal deminent Caption A).