Context:
Recent study revealed that the South American lungfish genome grew massively during the past 100 million years.
Relevance:
Facts for Prelims
South American Lungfish:
- Known scientifically as Lepidosiren paradoxa, this species is a freshwater lungfish.
- It represents the closest living link to the first land vertebrates, sharing a lineage that dates back over 400 million years.
- Predominantly found in the sluggish and still waters of Brazil, Argentina, Peru, Colombia, Venezuela, French Guiana, and Paraguay.
Genetic Characteristics:
- Exceptional Genome Size: Possesses the largest genome recorded in any animal, with its DNA capable of extending up to 60 meters if stretched out, compared to about 2 meters for the human genome.
- Comparative Genome Size: The lungfish’s genome is over 50 times larger than that of humans.
- Repetitive DNA: Approximately 90% of its genome consists of repetitive sequences.
Historical and Biological Insights:
- Emerged during the Devonian Period, a crucial era in evolutionary history when aquatic life began transitioning to terrestrial forms.
- This period marked the evolution of fish with specialized lungs and robust fins, setting the stage for the rise of tetrapods.
Adaptive Features:
- Respiratory Adaptation: Unlike typical fish that rely solely on gills, the South American lungfish has developed lung-like organs to aid in breathing.
- Habitat Adaptation: Thrives in oxygen-poor environments such as the swampy regions of the Amazon and Parana-Paraguay River basins, supplementing its aquatic oxygen intake with air-breathing.
-Source: The Hindu
