Question

Define the following terms related to variability during clonal propagation.

a.Ramet

b.Oret

c.Off-type

d. True-to-type

e. Genetic variation

f. Epigenetic variation

Answer 1

a. Ramet- When the clonal colony or genet produces a group of genetically identical individuals in plants originated by means of vegetative propagation and not sexually from a single parent, then individuals in such a population are called ramet.

b. Ortet- The original plant from which a clone has been derived.

c. Off-type- It refers to any plant which is not a part of the variety as it deviates in one or more characteristics from the traits where it is derived from.

d. True-to-type- It refers to the production of the same type of plants via vegetative propagation from the solitary parent. The clones are a group of morphologically and genetically similar individuals.

e. Genetic variation- It is the variation produced as a result of sexual reproduction where the offsprings produced inherits genetic material from two different gametes. Clonal diversity degree of intermingling of clones in the vegetative reproduction influence the mating and fertility of individual. Biparental inbreeding decrease the level of genetic variation. High rate of clonal propagation should increase the effective number of alleles and heterozygosity while opposite effect is observed on genetic diversity.

f. Epigenetic variation- It refers to the heritable changes or variations in gene expression that occurs without a change in DNA which contributes to phenotypic diversity. Clones which are produced by means of clonal propagation lack variations but epigenetic reprogramming mechanisms associated with meiosis can be evaded through which it is possible to produce epigenetic variation in asexuals.