Autopolyploidy Vs Allopolyploidy

Autopolyploidy vs. Allopolyploidy: Understanding Polyploidy in Plants

Polyploidy, the condition of possessing more than two complete sets of chromosomes, is a significant evolutionary force, especially in plants. This phenomenon can arise through two primary mechanisms: autopolyploidy and allopolyploidy. While both result in increased chromosome numbers, they differ significantly in their origins and genetic consequences. This article will delve into the distinctions between autopolyploidy and allopolyploidy, clarifying their mechanisms, impacts, and evolutionary significance.

I. Autopolyploidy: Doubling Within a Species

Autopolyploidy occurs when an organism duplicates its own chromosome set. This typically happens through a failure of chromosome segregation during meiosis (reductional division), resulting in diploid gametes (2n instead of n). When these diploid gametes fuse during fertilization, the resulting zygote is tetraploid (4n), containing four sets of chromosomes derived from a single species. Further rounds of chromosome doubling can lead to higher ploidy levels (e.g., octoploid, 8n; dodecaploid, 12n).

Mechanism: The most common mechanism involves the non-disjunction of chromosomes during meiosis I or II. This can be triggered by various factors, including environmental stressors such as temperature fluctuations or exposure to certain chemicals. Colchicine, a chemical that disrupts spindle fiber formation, is often used experimentally to induce autopolyploidy.

Consequences: Autopolyploids often exhibit increased cell size, larger organs, and altered gene expression compared to their diploid progenitors. However, they frequently suffer from reduced fertility due to the difficulties of pairing homologous chromosomes during meiosis. This is because multiple homologous chromosomes are present, leading to complex pairing configurations and irregular chromosome segregation.

Example: Many commercially important crops, such as potatoes ( Solanum tuberosum) and bananas, are autopolyploids. The increased size and yield are beneficial for cultivation, even though their fertility might be compromised.

II. Allopolyploidy: Combining Different Species

Allopolyploidy, in contrast to autopolyploidy, arises from the hybridization of two different species followed by chromosome doubling. When two species with different chromosome numbers hybridize, the resulting offspring is typically sterile because the chromosomes cannot pair properly during meiosis. However, if chromosome doubling occurs in this hybrid, each chromosome now has a homologous partner, restoring fertility. This creates a new allopolyploid species with a combined genome from its parental species.

Mechanism: The process typically begins with the formation of an interspecific hybrid through the fusion of gametes from two distinct species. This hybrid is usually sterile due to chromosome incompatibility. However, spontaneous chromosome doubling can occur through similar mechanisms as in autopolyploidy (meiotic errors or chemical induction). This doubling creates homologous pairs for all chromosomes, restoring fertility and creating a new allopolyploid species.

Consequences: Allopolyploids often exhibit unique characteristics that combine traits from both parental species. This can lead to novel adaptations and increased fitness in new environments. The combination of genomes can also lead to new gene interactions and expression patterns, contributing to phenotypic novelty.

Example: Wheat (Triticum aestivum) is a classic example of an allopolyploid. It arose from the hybridization of three different ancestral species, resulting in a hexaploid (6n) genome with three distinct subgenomes. This hybridization event was instrumental in the development of modern wheat's high yield and adaptability. Another example is cotton ( Gossypium hirsutum), a tetraploid species resulting from a hybridization event.

III. Distinguishing Autopolyploidy and Allopolyploidy

The distinction between autopolyploidy and allopolyploidy can be made through cytogenetic analysis, examining the chromosome morphology and pairing behaviour during meiosis. Autopolyploids will show multivalent chromosome pairing (more than two chromosomes pairing together) during meiosis, whereas allopolyploids typically exhibit bivalent pairing (two homologous chromosomes pairing). Molecular techniques, such as genomic sequencing and phylogenetic analysis, can also provide valuable information to determine the origins and relationships of the constituent genomes.

IV. Evolutionary Significance

Polyploidy has played a crucial role in plant evolution, contributing to speciation and diversification. Both autopolyploidy and allopolyploidy can lead to the rapid emergence of new species with unique characteristics. The increased genetic variation resulting from polyploidization provides raw material for natural selection, potentially leading to adaptation to new environments and ecological niches. Many successful and economically important plant species owe their existence to past polyploidization events.

V. Summary

Autopolyploidy and allopolyploidy are two distinct mechanisms that lead to polyploidy in plants. Autopolyploidy involves the duplication of a single species' chromosome set, while allopolyploidy combines the genomes of different species followed by chromosome doubling. Both processes can result in significant phenotypic changes, increased genetic variation, and the generation of new species. Understanding the differences between these two types of polyploidy is essential for comprehending the evolutionary dynamics and diversification of plants.

Frequently Asked Questions (FAQs):

1. Q: Are polyploids always larger than their diploid counterparts? A: While polyploids often exhibit increased cell and organ size, this is not always the case. The phenotypic effects of polyploidy are complex and influenced by various genetic and environmental factors.

2. Q: Is polyploidy more common in plants or animals? A: Polyploidy is far more common in plants than in animals. This is partly due to the greater tolerance of plants to changes in chromosome number.

3. Q: Can autopolyploids and allopolyploids hybridize? A: Yes, autopolyploids and allopolyploids, as well as different polyploids, can hybridize, leading to even more complex ploidy levels and genomic compositions.

4. Q: What are the implications of polyploidy for agriculture? A: Polyploidy is widely exploited in agriculture, as many important crop plants are polyploids. They often exhibit increased yield, larger fruits or seeds, and improved stress tolerance.

5. Q: How is polyploidy detected? A: Polyploidy can be detected through cytogenetic analysis (chromosome counting and examination), flow cytometry (measuring DNA content), and molecular techniques like genomic sequencing and PCR-based methods.

Search Results:

Difference Between Autopolyploidy and Allopolyploidy 5 Oct 2017 · The main difference between autopolyploidy and allopolyploidy is that autopolyploidy is the containment of multiple sets of chromosomes that are derived from the same species whereas allopolyploidy is the containment of multiple sets of chromosomes that are derived from different species.

What is the main difference between autopolyploid and … 15 Dec 2024 · In this article, we ‍will explore the definitions, characteristics, mechanisms, and⁤ implications of ⁣autopolyploidy and allopolyploidy, offering insights into their variations and the ‍impact⁣ they have ⁢on the plant kingdom.

American Journal of Botany - Botanical Society of America 4 Mar 2024 · Our results suggest that observations of polysomic inheritance can lead to relabeling of taxonomically allopolyploid species as autopolyploid and highlight the need for further cytogenetic and genomic investigation into polyploid origins and inheritance types.

Double trouble: taxonomy and definitions of polyploidy 7 Nov 2016 · For the question of autopolyploidy vs allopolyploidy, we feel strongly that much more information is needed on the genetic behavior of polyploids across a wide diversity of genera to understand the shape of the polysomic–mixosomic–disomic continuum and how it relates to taxonomy-based categorizations (Fig. 3).

Changes in Chromosomal Number: Polyploidy - University of … Autopolyploidy results from duplication of full chromosomal sets in one species . Autopolyploids differ in phenotype "quantitatively" from their parents. That is, the only difference is in ploidy level, or number of chromosome sets, not in kinds of chromosomes.

Autopolyploidy - an overview | ScienceDirect Topics Autopolyploids are formed by intraspecific hybridization of diploid populations, whereas allopolyploids are formed by interspecific hybridization.

Autoploidy vs Allopolyploidy - What's the difference? - WikiDiff As nouns the difference between autoploidy and allopolyploidy is that autoploidy is (genetics) the condition of being autoploid while allopolyploidy is (genetics) a form of polyploidy (having more than the usual number of chromosomes) that results from the interbreeding of different species.

Autopolyploidy vs. Allopolyploidy — What’s the Difference? 21 Mar 2024 · Autopolyploidy involves chromosome duplication within a single species, while allopolyploidy results from hybridization between species, combining distinct sets of chromosomes. Autopolyploidy occurs when an organism has more than two sets of chromosomes, all originating from a single species.

Polyploidy: Differences between Autopolyploidy and Allopolyploidy … 6 Jun 2023 · Autopolyploidy appears when an individual has more than two sets of chromosomes, both from the same parental species. Allopolyploidy, on the other hand, occurs when the individual has more than two copies but from different species.

Polyploidy and its effect on evolutionary success: old questions ... Stebbins distinguished three major types of polyploids: autopolyploids, allopolyploids and segmental allopolyploids (Stebbins, 1947). In autopolyploids all genomes are identical or very similar and arise via genome duplication within the same species (Stebbins, 1947; Lewis, 1980).

Autopolyploidy vs. Allopolyploidy | Writing in Biology - Section 1 29 Oct 2019 · One important difference between allopolyploidy and autopolyploidy is how they come to be. Meaning, an allopolyploid individual is made when two parent individuals come together with a different number of their pairs of chromosomes (one gamete has 3, the other 2) to form a hybrid that cannot produce viable gametes.

Allopolyploidy vs. Autopolyploidy - What's the Difference? | This vs… Allopolyploidy and autopolyploidy are two types of polyploidy that involve an increase in the number of chromosome sets. While allopolyploidy arises from hybridization between different species, autopolyploidy results from chromosome doubling within the same species.

Autopolyploidy vs Allopolyploidy: What's the Difference in Plant ... Allopolyploidy: involves the increase in the number of sets of chromosomes from different species, occurring when two different species hybridize and their chromosomes combine. Autopolyploidy can have negative effects on plant fertility due to the altered phenotype and reduced fertility in organisms with autopolyploidy.

Natural neopolyploids: a stimulus for novel research 14 Feb 2025 · This phenomenon can arise through autopolyploidy, where the additional chromosomes are derived from the same species, typically due to errors during cell division. Alternatively, allopolyploidy involves the combination of chromosome sets from different species through hybridization and genome duplication.

Difference Between Autopolyploidy and Allopolyploidy Key Difference - Autopolyploidy vs Allopolyploidy Polyploidy refers to a type of a chromosomal aberration which results in an organism with three or more sets of chromosomes, instead of the normal diploid condition.

Allopolyploidy & Autopolyploidy | Speciation & Examples 21 Nov 2023 · Allopolyploidy is more common than autopolyploidy, particularly in plants. For allopolyploidy to occur, the two different species must have a way of physically combining their gametes.

Polyploidy: Definition, Types, Mechanism, Advantages - Embibe 9 Feb 2025 · The three kinds of polyploidy are allopolyploidy, autopolyploidy, and auto-allopolyploidy. Allopolyploidy: a polyploid individual or strain with a chromosomal set made up of two or more chromosome sets originating from other species that are more or less complete. Examples: the allohexaploid Triticum aestivum, allotetraploid Gossypium, and mules.

Differentiate between autopolyploids and allopolyploids. - Vedantu Both autopolyploidy and allopolyploidy are types of euploidy and the major differences between both of them is that in case of autopolyploids, the genome comprises of several sets of chromosomes isolated from identical species while in case of allopolyploids the genome comprises several sets of chromosomes isolated from varying species.

Differentiate between.Autopolyploids and allopolyploids The polyploids which have evolved from plants with the lower chromosome number by a direct increase of the number are called autopolyploids. Whereas the polyploids which have evolved by increase in chromosome number after crossing with other species are called allopolyploids.

Autopolyploidy - an overview | ScienceDirect Topics Classically, polyploidy is classified into two extreme situations: autopolyploidy and allopolyploidy. An autotetraploid plant has four copies of the same chromosome set. In contrast, an allotetraploid or amphidiploid plant has two diploid sets of chromosomes derived from distinct species.

Autopolyploidy vs Allopolyploidy - What's the difference? As nouns the difference between autopolyploidy and allopolyploidy is that autopolyploidy is the property of being autopolyploid while allopolyploidy is (genetics) a form of polyploidy (having more than the usual number of chromosomes) that results from the interbreeding of different species.

Autopolyploidy Vs Allopolyploidy