Key Difference – Allogamy vs Xenogamy
The key difference between Allogamy and Xenogamy is that Allogamy refers to the fertilization of an ovum with sperms of another individual of the same species while xenogamy refers to the union of two unrelated or genetically different individuals of the same species. Xenogamy is a type of allogamy.
Pollination is referred to the process of transferring pollen from male reproductive organ to female reproductive organ for the fertilization (syngamy). In other words, pollination means transferring of pollen from anthers to stigma of the flower. Pollination is two ways; self pollination and cross pollination. Self pollination is less favored and it is the process of transferring pollen from anther to stigma of the same flower or stigma of the different flower of the same plant. Cross pollination is the process of transferring pollen from anthers of the one plant to stigma of another plant of the same or different species. Cross pollination has an evolutionary advantage since it produces genetically diverse, more fitness offsprings. Allogamy and Xenogamy are two terms related to cross pollination.
CONTENTS
1. Overview and Key Difference
2. What is Allogamy
3. What is Xenogamy
4. Similarities Between Allogamy and Xenogamy
5. Side by Side Comparison – Allogamy vs Xenogamy in Tabular Form
6. Summary
What is Allogamy?
Allogamy is referred to the fertilization of an egg cell with one individual with the sperm of another individual. It is a type of a cross fertilization. As an example, fertilization occurs in humans is a type of allogamy. Allogamy can occur via two ways; geitonogamy and xenogamy. Geitonogamy is referred to the transferring of pollens of one flower to the stigma of another flower of the same plant. Genetically it is a type of self pollination. However, since two individual flowers are involving, it is described under allogamy. Xenogamy occurs between two genetically different individuals of the same species.
Figure 01: Allogamy
Allogamy can occur between two flowers of the same plant, or between two flowers of two individual plants or strains. Allogamy is useful in masking deleterious effects of recessive alleles in the progeny.
What is Xenogamy?
Xenogamy is a type of allogamy in which the union of gametes occurs between two genetically unrelated individuals of the same species. It is a form of cross pollination in plants. Since xenogamy occurs between two genetically different parents (two genotypes), it increases the genetic variability in offsprings. Thus, enhances the overall fitness of a species.
Figure 02: Xenogamy
Xenogamy is an evolutionary important process that occurs in nature and in agriculture. In an evolutionary context, xenogamy is a fundamental process of producing more fitness organisms and retaining them over fewer fitness individuals by the natural selection. More fitness organisms will continue to survive in the environment and it is important for the evolution of a species. Xenogamy is important for reducing the homozygosity in breeding populations as well. And also it allows the reintroduction of alleles or introduction of new alleles into a population.
What are the Similarities Between Allogamy and Xenogamy?
- Allogamy and Xenogamy occur between two individuals.
- Both include cross pollination methods.
What is the Difference Between Allogamy and Xenogamy?
Allogamy vs Xenogamy |
|
| Allogamy refers to the fertilization between an ovum of one individual with a sperm of another individual of the same species. | Xenogamy refers to the union of two genetically unrelated individuals of the same species. |
| Types | |
| Allogamy includes xenogamy and geitonogamy. | Xenogamy is one type. |
| Involving Individuals | |
| Allogamy can occur between two flowers of the same plant or two flowers of the different plants. | Xenogamy occurs between two different plants. |
| Reducing Homozygosity | |
| One way of allogamy (geitonogamy) does not reduce the homozygosity. | Xenogamy always reduces homozygosity. |
| Genetic Variability among the Offsprings | |
| Geitonogamy produces genetically identical offspring. | Xenogamy produces genetically different offspring. |
| Increasing the Fitness of the Species | |
| Geitonogamy does not increase the fitness of the species. | Xenogamy increases the fitness of the species. |
| Evolutionary Importance | |
| Geitonogamy is not evolutionarily important. | Xenogamy is evolutionarily important. |
Summary – Allogamy vs Xenogamy
Allogamy and Xenogamy are words used interchangeably for cross pollination or cross fertilization. However, allogamy includes geitonogamy that refers to a type of self pollination. Allogamy is the fertilization of an ovum with the sperm of another individual (another flower of the same plant or another plant). Xenogamy always occurs between two genetically unrelated individuals of the same species. This is the difference between allogamy and xenogamy.
Reference:
1.“Xenogamy.” Species, Genetic, Alleles, and Homozygous – JRank Articles. Available here
2.“Allogamy.” Allogamy – an Overview | ScienceDirect Topics. Available here
Image Courtesy:
1.’Cross Pollination (468246966)’By Snap® from Kuwait, Kuwait – Cross Pollination, (CC BY 2.0) via Commons Wikimedia
2.’Cross pollination’By Ali Niaz (CC BY-SA 4.0) via Commons Wikimedia