Glossary Plant Breeding

Renaturation. The return to the native configuration of a denatured macromolecule (such
as DNA or protein). In case of DNA, annealing is the process, which brings back the
denatured DNA to its original state.
Renner Effect. Competition among the four genetically different megaspores (formed by
meiosis) as to which one will form the embryo.
Repair. Restoration of the original structure (biological activity) of damaged DNA by
any one of the recovery mechanisms. Repair includes both reversion and replacement
of an induced lesion.
Replicase. An enzyme catalysing the process of replication of nucleic acids.
Replication Fork. The point at which the two strands of DNA are separated to allow
replication of each strand.
Replication. In statistics, the process of repeating the same treatment to different plots. It
is essential for estimation of experimental error. In this process, the same treatment or
the same replica is planted twice, thrice or even four times. The process of replication
is something that amounts to sampling. In genetics, replication implies DNA synthesis
through which a new replica (copy) of the original DNA is produced.
Replicon. A chromosomal region under the influence of one adjacent replicationinitiation
locus. It is a unit of replication, represented by a sequentially replicating
linear or circular DNA structure.
Reporter Gene. A gene whose phenotypic expression is used to study tissue-specific
promoter and enhancer activities in transgenes. In essence, it reports the presence of
other gene or genes.
Repressor Protein. A molecule that binds to the operator and prevents transcription of an
operon.
Repressor. A protein that binds to a cis-acting element such as an operator or a silencer,
thereby preventing transcription from an adjacent promoter.
Reproduction. The propagation of an organism, a cell, or an organelle by one like itself.
Reproduction may occur by sexual means (sexual reproduction) or by asexual means
(asexual reproduction).
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