The mitogenome of the California grunion (Leuresthes tenuis)

Abstract

We report the complete mitogenome for the California grunion (Leuresthes tenuis), a beach-spawning silverside fish endemic to eastern Pacific coastal waters of California, USA and Baja California, Mexico. Approximately, 28,428 short reads from a shotgun gDNA library were mapped to a reference mitogenome of Menidia menidia. The resulting L. tenuis mitogenome is 16,719 bases in length. We further provide a Bayesian phylogenetic tree showing relationships among L. tenuis and other Atheriniform fishes.

Keywords:

• Grunion
• Atheriniformes
• Atherinopsinae

The California grunion Leuresthes tenuis (Atheriniformes) historically ranges from south of Point Conception, California, USA, to Bahía Magdalena, Baja California Sur, Mexico (Miller and Lea 1972), with reports over the last decade north to San Francisco Bay and Tomales Bay (Yoklavich et al. 2002, Jahn 2004, Roberts et al. 2007, Martin et al. 2013). California grunion and its sister species, the Gulf grunion L. sardina, are the only fish species known to spawn on sandy beaches and deposit fertilized eggs in the sand to incubate terrestrially (Thompson 1919, Walker 1952, Martin 2015). Here, we provide the first complete mitogenome of L. tenuis (GenBank accession: MN181432).

Genomic DNA was extracted from a single larval L. tenuis individual hatched from gametes stripped from adults collected at Doheny State Beach, Dana Point, CA, USA, (33.461667, −117.687222) on 23 April 2016, using the QIAgen DNeasy Tissue Kit (Valencia, CA, USA) and used to construct a next-generation sequencing library (Illumina HiSeq2500) for a separate molecular marker development project. Specimen DNA is archived at the Natural History Museum of Los Angeles County (NHM) under accession number LACM:T-001274. Over 4.7 million 250-PE reads were processed for quality in Trimmomatic V0.36 (Bolger et al. 2014). The remaining 3.5 million reads were mapped to a Menidia menidia mitogenome (GenBank no: AB370893) in Geneious 10.2.3 (Kearse et al. 2012), and all polymorphic sites were inspected for sufficient coverage (50–438x). Annotations were transferred from M. menidia, and the resulting full L. tenuis mitogenome (GenBank no: MN181432, NC_044649) was then aligned with available Atheriniform mitogenomes (GenBank accessions in Figure 1) using MAFFT 7.0 (Katoh et al. 2019). A Bayesian phylogram was constructed using MrBayes 3.2.2 (Ronquist and Huelsenbeck 2003, Ronquist et al. 2012).

Figure 1. Bayesian phylogram of Atheriniform mitogenomes. Node support values are Bayesian posterior probabilities.

The 16,719 base pair L. tenuis mitogenome possesses 13 protein-coding genes, 22 transfer RNA genes (tRNA), 2 ribosomal RNA genes (rRNA), and a D-loop (control region), approximately 200–300 bp longer than other Atheriniform species. Tree reconstruction places L. tenuis in a group with B. microlepidotus and Odontesthes sp. (Figure 1) with M. menidia and Chirostoma humboldtianum comprising a sister group. The resulting Atheriniform mitogenomes phylogeny yields an incomplete phylogenetic reconstruction, not fully reflective of published relationships among Atheriniform fishes (Dyer and Chernoff 1996, Parenti 2005, Campanella et al. 2015). Future work should focus on comparisons among mitogenomes of the two Leuresthes species, L. tenuis, and L. sardina and other close relatives, to further resolve relationships among these eastern Pacific endemic species.

Acknowledgments

Thanks to William Lundt for assistance with archival of the L. tenuis specimen DNA at NHM. Adult grunion used to generate the specimen in this work were collected under CDFW scientific collecting permit #SC 3211 to KAD (and CSUF IACUC-approved protocol #17-R-06).

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

Funding for this work was provided to RPW by California State University, Fullerton startup funds.