explain about polyploidy
http://en.wikipedia.org/wiki/Polyploid
Polyploidy is a phenomenon in genetics where an organism has more than two complete sets of chromosomes. This is in contrast to the normal condition, called diploidy, where organisms have two sets of chromosomes, one from each parent.
To explain polyploidy in more detail, we need to first understand the concept of chromosomes. Chromosomes are long, thread-like structures found in the nucleus of cells that contain DNA, the genetic material. In humans, for example, we have 23 pairs of chromosomes, for a total of 46. Each pair consists of one chromosome inherited from the mother and one from the father.
Polyploidy can occur in two ways: autopolyploidy and allopolyploidy. Autopolyploidy happens when an organism has extra sets of chromosomes from its own species. This can occur due to errors during cell division, resulting in the replication of chromosomes without subsequent separation. As a result, the offspring have more than two sets of chromosomes.
Allopolyploidy, on the other hand, occurs when an organism has additional sets of chromosomes from different but closely related species. This can happen when two species reproduce and produce a hybrid offspring with duplicate sets of chromosomes.
Polyploidy can have significant effects on the phenotype and the characteristics of an organism. In some cases, it can lead to larger cell sizes, increased vigor, and altered gene expression. Polyploidy can also contribute to the evolution of new species, as the extra sets of genetic material provide more opportunities for genetic variation and adaptation.
To determine if an organism is polyploid, scientists typically use techniques such as karyotyping, which involves examining the chromosomes under a microscope and counting the sets. Molecular methods, such as flow cytometry or DNA sequencing, can also be used to determine the ploidy level.
In summary, polyploidy is a genetic condition where an organism has more than two complete sets of chromosomes. It can occur through errors during cell division or by the hybridization of closely related species. Polyploidy can have significant effects on the organism's characteristics and evolution, and its determination usually requires specific laboratory techniques.