The dragonfly effect

The Black Petaltail (Tanypteryx hageni) is one of eleven dragonfly species in the family Petaluridae. The family’s name recognizes the large, wide claspers at the end of the male abdomen (resembling the petals of a flower), which are used to clasp the female while mating. The Black Petaltail is found in western North America, from British Columbia in Canada to southern California in the US, but other species of petaltail are found in Australia, New Zealand, Chile, eastern North America and Japan. Like other dragonflies petaltails have an aquatic juvenile stage (a larva or nymph), but these are not found in ponds or streams like the majority of dragonfly species; petaltails live in fens and bogs, places near springs and small streams where the soils are consistently saturated with water.

Adult Tanypteryx hageni, courtesy of Carey Kerst, AMNS (used with permission)

Most species of petaltail construct and maintain a burrow in these fens—the ‘Hobbits’ of the dragonfly world, living in a hole in the ground. The burrow fills with water, and the petaltail nymphs live in these burrows for multiple years before emerging as adults—the Black Petaltail is thought to take five years to develop. Black petaltail fens are usually found in mountain valleys, in large meadows surrounded by forests. As such habitats can be quite isolated, and are also subject to increasing risk from wildfires in these areas. Understanding how these dragonflies are adapted to these unique habitats, and how their long development times influence their populations genetics, will be some of the questions that can be addressed with a quality genome assembly.

Today, we share the chromosome-length assembly for the black petaltail (Tanypteryx hageni). The draft assembly was generated by Ethan Tolman, Paul Frandsen, Jessica Ware, Christopher Beatty and colleagues at the American Museum of Natural History colleagues at the American Museum of Natural History. Data from two PacBio Sequel II SMRT cells generated at the BYU sequencing center was assembled with Hifiasm (Cheng et al., 2021). We upgraded the draft to chromosome-length using Hi-C data from a hemolymph sample from a juvenile petaltail not unlike the one you can see in the photo below, collected by Christopher Beatty in 2022 in the Lassen National Forest in California.

Juvenile nymph Tanypteryx hageni courtesy of Christopher Beatty (AMNS)

Funding for this project was provided by the College Undergraduate Research Award from the College of Life Sciences at Brigham Young University. We are also grateful for Grant #8709-09 from the National Geographic Society Committee for Research and Exploration.

We are also very proud to announce that Chirag Maheshwari, the DNA Zoo team member who helped bring this genome assembly to it's chromosome-length glory, has just been awarded the Atlas Fellowship for outstanding high school students. Congratulations!

Check out the interactive Juicebox.js instance below for a contact map of the 9 chromosomes of T. hageni. And don't forget to visit the assembly page for more info and links!

The lion king

The lion is a large cat native to Africa and India. Lions have captured our imagination for centuries, from the paleolithic cave art to modern movies and characters in books, lions are at the top of the food chain. The lions have long been associated with kingship, nobility and commanding power. The Swahili word for lion, simba means "king," "strong," and "aggressive", and the sacred "Lion God" in India is a fierce avatar of the Hindu god Vishnu.

Hubert, the lion from the Oklahoma City Zoo who's genome assembly we are sharing today. Photo credit: Andrea Johnson

Did you know that lions are the only cats that live in large social groups? They are called prides. A pride can have from 3 to 30 lions and is made up of lionesses (mothers, sisters, and cousins) and their cubs, along with a few unrelated adult males. The pride has a close bond and is not likely to accept a stranger. Both males and females scent mark to define their territory.

A lion’s life is filled with sleeping, napping, and resting. Over the course of 24 hours, lions have short bursts of intense activity, followed by long bouts of lying around that total up to 21 hours!

Are lions in trouble? It is estimated that there are between 6,000 and 10,000 African lions in Africa. The Asian lion which used to be found across the Middle East and India is represented by only about 500 to 674 individuals, with more than half living in a reserve that used to be royal hunting grounds in an area of dry teak forest called the Gir Forest, now under national protection by the Indian government. The remainder of this particular subspecies lives in zoos.

Due to many issues such as disease, hunting by humans, and loss of habitat, the conservationists are very concerned about the population of lions in Africa. The International Union for Conservation of Nature (IUCN) classifies lions as Vulnerable, but they note that the vast majority of the population is inferred to have declined at a rate that meets the criteria for Endangered. The Asiatic lion currently exists as a single subpopulation in India, and is thus vulnerable to extinction from unpredictable events, such as an epidemic or large forest fire and is fully protected in India.

Today, we share the chromosome-length assembly for the South African lion (Panthera leo krugeri). The assembly was generated from a sample donated by Hubert, the king of the Oklahoma City Zoo lion pride. Thank you to Jennifer D’Agostino, DVM, DACZM, Candice Rennels, Director of Public Relations, Rebecca Snyder, Director of conservation and science and others at the Oklahoma City Zoo for their help with this sample!

This is a $1K de novo genome assembly. See our Methods page for details on the procedure. We gratefully acknowledge the Pawsey Supercomputing Center for the computational support for this assembly, and the computational assistance from the DNA Zoo Australia team at the University of Western Australia. Check the interactive map of Hubert's chromosomes below, and look for more data and info on the assembly page!

SRA update for 300 genome assemblies

We are excited to report that with our last assembly release we've hit the 300 assemblies mark, which means it's time to do some raw sequencing data upload to NCBI Sequence Read Archive!

The new data have now been uploaded under our usual BioProject accession PRJNA512907 (some more data can be found under collaborative bioproject accessions like PRJNA679437). Overall, as of today the uploaded data cover Hi-C and WGS data spanning 605 experiments and 40,240,196,863,263 bases!

We thank Illumina, Baylor College of Medicine GARP core, Macrogen, Novogen and the Broad Institute for their help with the data production! And thank you to Maya and Judah for the celebratory postcard!

As always, we share the data without restrictions: see our data usage policy here.

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