Polyploidisia

Polyploidisia is the study of polyploidy and its biological consequences, focusing on organisms that possess more than two complete sets of chromosomes. The term combines polyploid (manyfold) with -ia indicating a field of study. In practice, polyploidisia encompasses the detection, formation, evolution, and ecological implications of polyploid genomes across diverse life forms.

Polyploidization occurs through whole-genome duplication. Autopolyploidy arises when an individual duplicates or retains its own genome, often via unreduced gametes, resulting in a plant or organism with additional chromosome sets derived from the same species. Allopolyploidy results from hybridization between distinct species followed by chromosome doubling, yielding a stable organism with chromosome sets from different origins. Endopolyploidy describes higher ploidy levels in certain tissues without whole-organism polyploidy.

Polyploid genomes can exhibit increased cell size, altered development, and novel gene interactions. The redundancy allows mutation and divergence of gene duplicates, contributing to stress tolerance, ecological breadth, and rapid speciation. Polyploidy is especially common in plants; many crops are polyploid, such as wheat (hexaploid) and cotton (tetraploid). In animals and fungi, polyploidy is less frequent but documented in certain lineages and life stages.

Polyploidization can be studied via cytogenetics, flow cytometry to estimate genome size, and genomic sequencing for duplication history. Experimental induction uses antimitotic agents like colchicine and oryzalin.

In scientific discourse, polyploidisia also addresses genome stability, meiosis, fertility, and speciation dynamics, as well as applications in agriculture and considerations for conservation and biodiversity.