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**Occurrence of Autogamy in Different Organisms:**

– **Protists:**
– Paramecium aurelia and Tetrahymena rostrata undergo autogamy under nutritional stress.
– Paramecium aurelia experiences clonal aging and rejuvenation through meiosis.

– **Allogromia laticollaris:**
– Alternates between sexual and asexual reproduction.
– Shows autogamous behavior under nutritional stress.

– **Flowering Plants:**
– About 10-15% of flowering plants are predominantly self-fertilizing.
Self-pollination can be autogamous or geitonogamous.

– **Fungi:**
– Homothallic fungi like Cochliobolus and Pneumocystis jirovecii undergo selfing.
– Original mode of sexual reproduction in fungi likely homothallic.

**Genetic Consequences of Autogamy:**

– **Reduced Genetic Variation:**
– Self-fertilization reduces genetic variation within offspring.
– Loss of heterozygous loci can lead to harmful recessive allele expression.

– **Inbreeding Depression:**
– Selfing in plants can result in inbreeding depression after several generations.
– Heterozygous loci decrease by half in each successive generation.

**Advantages and Disadvantages of Autogamy:**

– **Advantages:**
– Ensures reproduction in isolated populations.
– Preserves favorable genetic characteristics.
– Rapid adaptation to changing environments.

– **Disadvantages:**
– Increases risk of genetic disorders.
– Limits genetic diversity.
– Accumulation of deleterious mutations.

**Evolutionary Aspects of Autogamy:**

– **Shift to Self-Fertilization:**
– Common in plants.
– Likely evolved separately in flowering plants and unicellular species.

– **Maintaining Autogamy:**
– Not fully understood due to low genetic variation in progeny.

**Mechanism and Examples of Autogamy:**

– **Mechanism:**
– Involves self-fertilization within the same individual.
– Enhances reproductive success in isolated populations.

– **Examples:**
– Some plants like peas and tomatoes self-pollinate.
– Hermaphroditic animals can self-fertilize.
Autogamy in fungi.

This organization will help in understanding the various facets of autogamy across different organisms, its genetic implications, advantages, disadvantages, evolutionary significance, and the mechanisms and examples of autogamy in nature.

Autogamy (Wikipedia)

Autogamy or self-fertilization refers to the fusion of two gametes that come from one individual. Autogamy is predominantly observed in the form of self-pollination, a reproductive mechanism employed by many flowering plants. However, species of protists have also been observed using autogamy as a means of reproduction. Flowering plants engage in autogamy regularly, while the protists that engage in autogamy only do so in stressful environments.

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