Aneuploidy Figure An Example of Allopolyploid is Cotton Examples of allopolyploids are cotton — 13 pairs and 53 chromosomes, wheat — 7 pairs and 42 chromosomes. What are the Similarities Between Autopolyploidy and Allopolyploidy? Both types belong to the polyploidy condition where the number of chromosomes is increased compared to the normal count. Both types are used in developing hybrid varieties.
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Key Terms: Allopolyploidy, Autopolyploidy, Hybrid Species, Meiosis, Mitosis, Nondisjunction of Chromosomes, Polyploidy, Sympatric Speciation What is Autopolyploidy Autopolyploidy refers to a type of polyploidy in which the chromosome complement consists of more than two copies of homologous chromosomes.
It occurs by the fusion of gametes of the same parent. Typically, most eukaryotic organisms are diploid in their lifetime. This means they possess two sets of chromosomes. Autopolyploidy arises by the doubling of the chromosome number of the diploid species.
Autopolyploidy can possess either three triploid , four tetrapolyploid , five pentapolyploid , six hexapolyploid or more copies of the same genome. Figure 1: Autopolyploidy Autopolyploidy can occur in two ways: nondisjunction of gametes and genome duplication.
The nondisjunction of chromosomes can occur in both mitosis and meiosis. The mitotic nondisjunction may occur in the early embryo , forming polyploid new individuals. In the meiosis, the fusion of a haploid gamete with a diploid gamete may also produce a triploid zygote. All chromosome sets in an autopolyploid individual are homologous to each other. Because of this, the aligning of the homologous chromosomes at the prophase 1 of meiosis 1 is difficult.
As an example, in triploidy, three homologous chromosomes occur in the cell, and only two can pair during cell division. The third chromosome segregates randomly. Therefore, the resulting gametes may contain unbalanced chromosome numbers of different chromosomes. This may produce an unbalanced number of chromosomes in the zygote. The unbalanced gene dosage may be lethal.
Autopolyploidy may occur by genome duplication as well. The genome duplication can occur by meiotic non-reduction of the gametes. The formation of the tetraploid zygote by the fusion of two diploid gametes is shown in figure 1. What is Allopolyploidy Allopolyploidy refers to a type of polyploidy in which the chromosome complement consists of more than two copies of chromosomes derived from different species.
It occurs when two species mate to produce a hybrid species. The mule which is produced by the mating of a male donkey with a female horse is an example of a hybrid. The mating of two different species may produce a sympatric species, which is infertile with both parental species due to the allopolyploidy. Figure 2: Wheat Sympatric speciation commonly occurs in wheat, which is a type of grass. The wheat pollen can fuse with other species in the same genus, producing sympatric species.
Wheat is a combination of three types of grasses. The meiosis occurs perfectly in these types of sympatric species since each type of chromosome set consists of another homologous chromosome set to pair. Similarities Between Autopolyploidy and Allopolyploidy Autopolyploidy and allopolyploidy are two types of cell division anomalies. Both autopolyploidy and allopolyploidy occur by the nondisjunction of sister chromatids or chromosomes during prophase 1 and prophase 2 respectively.
Both autopolyploidy and allopolyploidy lead to polyploidy where multiple sets of chromosomes occur in the nucleus.
Both autopolyploidy and allopolyploidy mostly occur in plants. Both autopolyploidy and allopolyploidy can occur naturally or under the influence of chemicals such as colchicine. Difference Between Autopolyploidy and Allopolyploidy Definition Autopolyploidy: Autopolyploidy refers to a type of polyploidy where the chromosome complement consists of more than two copies of homologous chromosomes. Allopolyploidy: Allopolyploidy refers to a type of polyploidy where the chromosome complement consists of more than two copies of chromosomes derived from different species.
Arise Autopolyploidy: Autopolyploidy arises by the fusion of gametes of the same species. Allopolyploidy: Allopolyploidy arises by the fusion of gametes of the different species. Consist of Autopolyploidy: An autopolyploid cell contains homologous chromosome sets. Allopolyploidy: All chromosome sets of an allopolyploid cell are not homologous. Cause Autopolyploidy: Autopolyploidy is mainly caused by nondisjunction of chromosomes. Allopolyploidy: Allopolyploidy is caused by mating of different species.
Meiosis Autopolyploidy: An autopolyploid cell does not undergo meiosis since it has arisen from one parent. Allopolyploidy: An allopolyploid cell can undergo meiosis.
Examples Autopolyploidy: Autopolyploidy is seen in crops such as wheat, oats, sugar-cane, potato, peanut, banana, and coffee. Allopolyploidy: Allopolyploidy is seen in crops such as wheat and animals such as mules.
Conclusion Autopolyploidy and allopolyploidy are two types of cell division anomalies, which lead to polyploidy. Autopolyploidy is the containment of multiple copies of chromosomes in the same parent.
Allopolyploidy is the containment of the multiple copies of chromosomes of different species. Autopolyploidy mainly occurs due to nondisjunction of chromosomes. Allopolyploidy occurs by the mating of different species. The main difference between autopolyploidy and allopolyploidy is the type of chromosome sets in their nucleus.
Reference: 1. Accessed 29 Sept. Image Courtesy: 2.
Difference Between Autopolyploidy and Allopolyploidy
Dodecaploid crops: some sugar cane hybrids  Some crops are found in a variety of ploidies: tulips and lilies are commonly found as both diploid and triploid; daylilies Hemerocallis cultivars are available as either diploid or tetraploid; apples and kinnow mandarins can be diploid, triploid, or tetraploid. Fungi[ edit ] Schematic phylogeny of the fungi. Red circles indicate polyploidy, blue squares indicate hybridization. From Albertin and Marullo,  Besides plants and animals, the evolutionary history of various fungal species is dotted by past and recent whole-genome duplication events see Albertin and Marullo  for review. Several examples of polyploids are known: autopolyploid: the aquatic fungi of genus Allomyces,  some Saccharomyces cerevisiae strains used in bakery ,  etc. In addition, polyploidy is frequently associated with hybridization and reticulate evolution that appear to be highly prevalent in several fungal taxa. Indeed, homoploid speciation hybrid speciation without a change in chromosome number has been evidenced for some fungal species such as the basidiomycota Microbotryum violaceum .
Allopolyploid: Definition, Speciation & Example
Difference Between Autopolyploidy and Allopolyploidy