Question

Jumping genes in maize were discovered by
A)Hugo de Vries
B)Barbara McClintock
C). H Morgan
D)Mendel

Answer 1

In maize, the color difference comes from transposons, or so-called jumping genes. These DNA stretches come out of their original genome location and then wedge themselves into another, random position. They can disrupt the activities of neighboring genes, including pigment genes, when they land.

Complete answer:
A transposable factor (TE, transposon, or jumping gene) is a sequence of DNA that can modify its location within a genome, causing or reversing mutations often and modifying the genetic origin and size of the cell. Transposition also results in the same genetic material being duplicated.

Barbara McClintock found that a chromosome-breaking locus could alter its location within a chromosome and discovered "jumping genes" when working on chromosome breakage in maize. In evening primrose, Hugo de Vries researched flower colour inheritance and named as a mutation the unexpected and unpredictable emergence of new characters. Morgan offered experimental evidence of the "chromosomal inheritance theory," first suggested by Sutton and Boveri, and linkage was also observed. On the basis of his findings, Mendel performed hybridization studies on garden pea vine, Pisum sativum and suggested "inheritance laws".

Hence, the correct answer is option (B)

Note: The first retrotransposition step happens when the transposable DNA is copied into RNA. The RNA fragment in the genome then hops to another location. However in order to be incorporated into the genome at the new site, the RNA must be copied back into DNA by an enzyme called reverse transcriptase.