Changes in chromosome number, Biology

Aneuploidy : One or inore chron~osomes of a normal set nlay bc lacking or present in excess. The term riullison~y refers to absence of both the chromosomes of a pair. Monosomy, trisomy, tetrasomy etc., refer to the occurrence of a given chromosome once, thrice, four times ctc., resycctively in a diploid organism.

Polyploidy : Refers to the occurrence of more than two sets of chromosomes in an individual. Most organisms are diploid, that is they have two sets of chromosomes in their somatic cells, but only one in their gametic cells. Polyploid organisms would be triploid when they have three sets of chromosomes, tetraploid if they have four sets and so on. Polyploidy occurs frequently in plants but is a rare phenomenon in animals. Polyploidy has been a common means of speciation in plants. Many of thc cultivated plants, such as wheat, oats, tobacco, potato, banana, coffee, sugarcane and many flowering plants are polyploids.

Plant breeders always attempt to induce polyploidy by artificial means to create new varieties. Polyploidy can be regarded as thc only means in bisexual organisms by which a new species could arise in one step.

Posted Date: 4/6/2013 1:13:05 AM | Location : United States







Related Discussions:- Changes in chromosome number, Assignment Help, Ask Question on Changes in chromosome number, Get Answer, Expert's Help, Changes in chromosome number Discussions

Write discussion on Changes in chromosome number
Your posts are moderated
Related Questions
examples on woody perennial Angiosperm species and herbaceous annual angiosperm species. thanks

write down the division of cryptogamae and phanerogamae

What is a community? What is the difference between the concepts of community and population? A community is a set of populations of living beings that live in the similar regi

The scutellum observed in a grain of wheat or maize is comparable to which part of the seed in other monocotyledons? 1. Cotyledon 2. Endosperm 3. Aleurone layer 4. Plum

Normal 0 false false false EN-IN X-NONE X-NONE MicrosoftInternetExplorer4

Some of the reason for increase in population is: 1.         Decline in death for an increase in life expectancy or longevity. 2.         Better medical facilities

In what ways is water lost from the body? Water is lost from the body by a) Evaporation (lungs and skin), b) Urination and defaecation (faeces always have water).

Chopping/grinding These are the processes by which the particle size of cereals, oil cakes and roughages including green fodders and crop residues is reduced employing various

What are the hormones produced by the testicles and the ovaries? The testicles make androgenic hormones, the major of them being testosterone. The ovaries make estrogen and pro

Q. What are the three kinds of protein fibers of the connective tissue proper? The matrix of the connective tissue proper is made of elastic fibers, collagen fibers and reticul