polyploidy

Examples of polyploidy in the following topics:

• Sympatric Speciation

  • Polyploidy is a condition in which a cell or organism has an extra set, or sets, of chromosomes.
  • Scientists have identified two main types of polyploidy that can lead to reproductive isolation, or the inability to interbreed with normal individuals, of an individual in the polyploidy state.
  • Polyploidy results from an error in meiosis in which all of the chromosomes move into one cell instead of separating.
  • Although polyploidy occurs occasionally in animals, it takes place most commonly in plants.
  • In the example shown, a normal gamete from one species fuses with a polyploidy gamete from another.

• Whole-Genome Duplication

  • Similar to gene duplication, whole-genome duplication is the process by which an organism's entire genetic information is copied, once or multiple times, which is known as polyploidy .
  • Sympatric speciation can begin with a chromosomal error during meiosis or the formation of a hybrid individual with too many chromosomes, such as polyploidy which can occur during whole-genome duplication.
  • Scientists have identified types of polyploidy that can lead to reproductive isolation of an individual in the polyploid state.
  • The other form of polyploidy occurs when individuals of two different species reproduce to form a viable offspring called an allopolyploid.
  • Triploid and tetraploid chromosomes are examples of polyploidy.

• Genome Evolution

  • There are various mechanisms that have contributed to genome evolution and these include gene and genome duplications, polyploidy, mutation rates, transposable elements, pseudogenes, exon shuffling and genomic reduction and gene loss.