The Ensembl gene annotation pipeline created gene models using protein alignments from the Universal Protein Resource (Uniprot) database, limited coelacanth complementary DNA data, RNA-seq data generated from L. The genome assembly was annotated separately by both the Ensembl gene annotation pipeline (Ensembl release 66, February 2012) and by MAKER 13. The coelacanth genome assembly has a contig N50 size (the contig size above which 50% of the total length of the sequence assembly can be found) of 12.7 kilobases (kb) and a scaffold N50 size of 924 kb, and quality metrics comparable to other Illumina genomes ( Supplementary Note 1, and Supplementary Tables 1 and 2).
DOS 2 BLOOD ISLAND PLUS
The draft assembly is 2.86 gigabases (Gb) in size and is composed of 2.18 Gb of sequence plus gaps between contigs. chalumnae genome has been reported previously to have a karyotype of 48 chromosomes 12. It was sequenced by Illumina sequencing technology and assembled using the short read genome assembler ALLPATHS-LG 11.
The African coelacanth genome was sequenced and assembled using DNA from a Comoros Islands Latimeria chalumnae specimen ( Supplementary Fig. Here we describe the sequencing and comparative analysis of the genome of L. Nevertheless, coelacanth research has felt the lack of large-scale sequencing data. In the past 15 years, targeted sequencing efforts have produced the sequences of the coelacanth mitochondrial genomes 7, HOX clusters 8 and a few gene families 9, 10. Latimeria has also been of particular interest to evolutionary biologists, owing to its hotly debated relationship to our last fish ancestor, the fish that first crawled onto land 6. Fascination with these fish is partly due to their prehistoric appearance-remarkably, their morphology is similar to that of fossils that date back at least 300 Myr, leading to the supposition that, among vertebrates, this lineage is markedly slow to evolve 1, 5. The discovery in 1997 of a second coelacanth species in Indonesia, Latimeria menadoensis, was equally surprising, as it had been assumed that living coelacanths were confined to small populations off the East African coast 3, 4. It was almost 15 years before a second specimen of this elusive species was discovered in the Comoros Islands in the Indian Ocean, and only 309 individuals have been recorded in the past 75 years (R. Latimeria is the only living member of an ancient group of lobe-finned fishes that was known previously only from fossils and believed to have been extinct since the Late Cretaceous period, approximately 70 million years ago (Myr ago) 1. This discovery is considered to be one of the most notable zoological finds of the twentieth century. Latimeria chalumnae, named after its discoverer 1, was over 1 m long, bluish in colour and had conspicuously fleshy fins that resembled the limbs of terrestrial vertebrates. In 1938 Marjorie Courtenay-Latimer, the curator of a small natural history museum in East London, South Africa, discovered a large, unusual-looking fish among the many specimens delivered to her by a local fish trawler.
Functional assays of enhancers involved in the fin-to-limb transition and in the emergence of extra-embryonic tissues show the importance of the coelacanth genome as a blueprint for understanding tetrapod evolution. Analyses of changes in genes and regulatory elements during the vertebrate adaptation to land highlight genes involved in immunity, nitrogen excretion and the development of fins, tail, ear, eye, brain and olfaction. Coelacanth protein-coding genes are significantly more slowly evolving than those of tetrapods, unlike other genomic features. Through a phylogenomic analysis, we conclude that the lungfish, and not the coelacanth, is the closest living relative of tetrapods. Here we report the genome sequence of the African coelacanth, Latimeria chalumnae. The modern coelacanth looks remarkably similar to many of its ancient relatives, and its evolutionary proximity to our own fish ancestors provides a glimpse of the fish that first walked on land. The discovery of a living coelacanth specimen in 1938 was remarkable, as this lineage of lobe-finned fish was thought to have become extinct 70 million years ago. Nature volume 496, pages 311–316 ( 2013) Cite this article
The African coelacanth genome provides insights into tetrapod evolution
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