The tube anemones studied appear to form a separate group from corals and sea anemones and display some similarities to medusae.
Another discovery reported in the article is that I. nocturnusand Pachycerianthus magnus (another species studied by Stampar's group, 77,828 base pairs) have linear genomes like those of medusae (Medusozoa), whereas other species in their class (Anthozoa) and indeed most animals have circular genomes.
The human mitochondrial genome (mitogenome), for example, comprises 16,569 base pairs.
The human nuclear genome comprises some 3 billion base pairs, for example.
The tube anemone Isarachnanthus nocturnusis only 15 cm long but has the largest mitochondrial genome of any animal sequenced to date, with 80,923?base pairs.
Small pieces of the animals' tentacles were used to sequence their mitogenomes.
After completing the study, the researchers published the genomes by gifting them to GenBan, a database maintained in the US by the National Center for Biotechnology Information (NCBI) at the National Institutes of Health (NIH).
The genomes of the two species hitherto available from databases were incomplete owing to the difficulty of sequencing them.
The necessary data could come from the sequencing of these species' nuclear genomes, which Stampar and his group intend to complete by the end of 2019.
The problem is that this only works with circular genomes.
The shape of the mitogenomes in these two species of tube anemone and the gene sequences they contain were more surprising than their size.
They used this technique to arrive at complete mitochondrial genomes for both species.
Reitzel and Macrander specialize in the use of bioinformatics to filter genomics data and assemble millions of small pieces of mitochondrial DNA into a single sequence.
Keeping this giant genome is probably more costly in terms of energy expenditure."
Source: Nature World News