Skates are cartilaginous fish whose body plan features enlarged wing-like pectoral fins, enabling them to thrive in benthic environments. However, the molecular underpinnings of this unique trait remain unclear. An multinational team of researchers investigated the origin of this innovation by developing the little skate (Leucoraja erinacea) as a genomically enabled model. Their analysis of a high-quality chromosome-scale genome sequence for the little skate shows that it preserves many ancestral jawed vertebrate features compared with other sequenced genomes, including numerous ancient microchromosomes.
“We know that animals with a backbone and a skeleton — known as vertebrates — including fish, possess myriad body shapes, but we understand little about the underlying processes controlled by genes,” said Dr. Tetsuya Nakamura, a researcher at Rutgers, the State University of New Jersey.
“In this research, we have identified the genetic mechanisms that create the unique characteristics of the skate body.”
Little skates are an Atlantic Ocean species of skate that are about 40-51 cm (16- 20 inches) long.
Their flat bodies feature enlarged, wing-like pectoral fins that allow the fish to thrive in sea-floor environments.
Their unique shape creates power for rapid forward propulsion.
They also use their flat fins to scoop and flip sand over them to hide from predators, covering everything but their eyes.
“We wondered how this unique body evolved during their evolution,” Dr. Nakamura said.
“If we came to understand how a skate evolved, perhaps it might give us clues to how other vertebrates developed their shapes.”
In conducting their analysis, Dr. Nakamura and colleagues connected the skates’ genotype — their unique sequence of DNA, with their phenotype — their physical properties, from body shape to biochemistry.
They also compared the little skate genome with various shark genomes, including that of the bamboo shark, with whom it shares…
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