You are studying a new strain of E. coli that can utilize the disaccharide melibiose very efficiently. You find that utilization depends on the enzyme melibiase, which is encoded by the gene Mel1. Mel1 is not expressed unless melibiose is present in the growth medium. You have isolated a mutation that causes constitutive melibiase activity, which you designate MelA–. P1 phage mapping experiments using a Tn5 insertion linked to Mel1 show that MelA– is not linked to Mel1. Moreover you find that when an amber suppressor is introduced into a MelA– mutant, normal melibiase regulation is restored. Classify the MelA– mutation on the basis of genetic properties,  make a proposal for the type of regulatory functions affected by the MelA– mutation?

#Question id: 4906

#Unit 8. Inheritance Biology

Shell coiling is a maternal effect phenotype controlled by S gene where S is dominant dextral phenotype over s sinistral phenotype. Dextral coiling Ss male snail was cross with sinistral coiling ss female snail, The phenotype of progeny is 

#Question id: 4907

#Unit 8. Inheritance Biology

Two corn plants are studied. One is resistant (R) and the other is susceptible (S) to a certain pathogenic fungus. The following crosses are made, with the results shown

R male X S female = all S progeny

R female X S male = all R progeny

Which of the following are correct about inheritance?

#Question id: 4908

#Unit 8. Inheritance Biology

Shell coiling of the snail is maternal effect phenotype control by S gene, where S Dextral is dominant over s sinistral. If snail sinistral coiled shell, which of the following statement is true

#Question id: 4909

#Unit 8. Inheritance Biology

A pattern of transmission where all offspring have the same phenotype as their mother is consistent with which type of non-Mendelian inheritance?

#Question id: 4910

#Unit 8. Inheritance Biology

For a trait known to be caused by a mitochondrial gene variant, there may be an occasional female that can transmit different phenotypes to her progeny on an apparently random basis. What situation might you suspect?

#Question id: 4911

#Unit 8. Inheritance Biology

Neutral petite mutations: