Question

List the genetic applications of Neurospora crassa, Chlamydomonas and Paramecium aurella.

Answer 1

Genetic application of Neurospora crassa:
N. crassa is a most favorite experimental material for researches of physiological genetics and cytogenetics due to its following peculiarities:
1. It has short life cycle and readily propagates asexually into unlimited population of given genotype.
2. It can be kept in pure cultures on chemically defined media.
3. Its eight linearly arranged ascospores in an ascus provide an opportunity to see that what has happened at meiosis because
(i) all the products of a single meiosis are preserved within one structure and cannot be confused with product of other meiotic division,
(ii) the positions of a particular ascospore within its ascus can be referred to the actual position of a nucleus in meiosis, as determined by the orientation of separating chromosomes on a division spindle.

Genetic application of Chlamydomonas:
Chlamydomonas is a good experimental genetical material because it is unicellular, economical to culture, and has chloroplast, whose genetics has given significant knowledge about the extra-chromosomal inheritance.

Genetic application of Plasmodium aurelia:
P. aurelia has been one of the favorite experimental material of geneticists due to the following reasons:
1.The fact that during autogamy and conjugation of it, the genetic machinery modifies but cytoplasm remains relatively unchanged and gives an opportunity to study the nuclear and cytoplasmic inter-relationships.
2. During autogamy the sister haploid nuclei fuse to bring about homozygosis for all genes and it represents a case of inbreeding.
3. The degeneration of macronucleus during autogamy and conjugation, and regeneration of macronucleus from a micronucleus, give an apparatus to study how the genotypes in both nuclei become different, so that macronucleus regulates the phenotype of the organism and micronucleus controls the reproductive activity of the organism.
4. During conjugation, sometimes an exchange of cytoplasmic non-nuclear but heritable entities occur which provides experimental evidences for extra-chromosomal or cytoplasmic inheritance.

Genetic application:

• Some of the genetically important organisms include Neurospora crassa, Chlamydomonas and Paramecium aurella.
• They are genetically applied in various experiments.