Lungfish, atau dipnoans, adalah vertebrata air tawar yang memiliki kemampuan luar biasa bernafas udara dan bertahan dalam lumpur kering selama bertahun-tahun. Sebagai saudara terdekat tetrapoda, ikan ini memiliki sirip berlobus dengan kerangka dalam yang berkembang baik. Hanya enam spesies yang masi

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Learn why lungfish have genomes that are far larger than the human genome, and how their expanded genomes shed light on evolution.

The human genome serves as a remarkable blueprint for our complex lives, although we’re not even close to having the largest genomes among animals. That distinction goes to lungfish, freshwater fish living in Africa, South America, and Australia. We have nearly 3 billion base pairs — which connect to form the “rungs” of the DNA ladder — in our genome. The South American lungfish blows us out of the water with 91 billion bases. However, genome size doesn’t quite have as much of an impact as it may seem. Although the South American lungfish genome is much larger than the human genome, that doesn’t make the species more complex than humans. Most of the material within lungfish genomes is essentially genetic fluff, repetitive DNA sequences that have replicated out of control. Find out why lungfish developed such gargantuan genomes compared to humans, and how their genomes could reveal key insights on their evolution hundreds of millions of years ago. Largest Genome of the South American Lungfish One of the classic clichés used to tell the story of evolution is the scene of a fish venturing onto land for the first time, awkwardly crawling with fins that would eventually transform into...

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Enzymatic digestion of various internal and external tissues of extant fishes yielded black to dark brown melanosome extracts. The eyes and skin are melanised in all species, but none show melanosomes in the brain, gonads or heart (Fig. 1 and Supplementary Fig. 1, Supplementary Table 2). The European river lamprey (hereafter river lamprey, Agnatha) exhibits the fewest melanosome-bearing tissue extracts, with melanosomes observed only in the eyes, skin and olfactory sac. The West African lungfish (hereafter African lungfish, Sarcopterygii) is the most heavily melanised taxon, with melanosomes in the gills, eyes, kidney, liver, lungs, peritoneum, skin, spleen and gut. In the studied Actinopterygii (Atlantic mackerel, European seabass and gilthead seabream, hereafter referred to as mackerel, seabass and seabream, as well as American eel and whiting), melanosomes consistently occur in the eyes, skin, spleen, kidney and, except in seabass, the peritoneum (Fig. 1 and Supplementary Fig. 1, Supplementary Table 2). In contrast, the studied Chondrichthyes (spotted skate, cuckoo skate, blackmouth catshark, small-spotted catshark and rabbitfish) show consistent melanisation only in the eyes and skin. In Chondrichthyes, melanosomes also occur in internal tissues, but their distribution varies among species: they are common in the gills, liver and peritoneum, rare in the gut...

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