Molecular Cytogenetic Analysis in Freshwater Prawns of the Genus Macrobrachium (Crustacea: Decapoda: Palaemonidae)

Abstract

Freshwater prawns of the genus Macrobrachium are one of the important components of circumtropical marine, estuarine, and freshwater environments. They have been extensively exploited for human consumption for many years. More than 250 species reflect the evolutionary success of this highly diversified group, with a complex and challenging taxonomy due to morphological variations and vast geographical distribution. Although genetic approaches have been used to clarify phylogenetic and taxonomic aspects of Macrobrachium species, cytogenetic information is still very scarce and mostly focused on chromosome number and morphology. Here, we present chromosome data for three species from the Neotropical region, M. carcinus, M. acanthurus, and M. amazonicum, and one species from the Oriental region, M. rosenbergii. Using conventional cytogenetic approaches and chromosome mapping of repetitive DNAs by fluorescence in situ hybridization (FISH), we identified numerical diversification of the diploid set, within and between both zoogeographic regions. These included M. acanthurus and M. amazonicum sharing diploid chromosomes of 98, while M. carcinus has 94, and M. rosenbergii has 118 chromosomes. Argentophilic sites are also variable in number, but they occur in a much higher number than 18S rDNA, representing two to 10 sites within the study species. Microsatellites repeat motifs are also abundant in the chromosomes, with a co-localization and uniform distribution along the chromosome arms, but completely absent in the AT-rich centromeric regions. As a whole, our study suggests that the 2n divergence was followed by a considerable rDNA diversification. The abundance of the exceptional amount of microsatellite sequences in the chromosomes also suggests that they are essential components of the Macrobrachium genome and, therefore, maintained as a shared feature by the species, the reason for which is yet unknown.

A chromosome-level genome assembly of the oriental river prawn, Macrobrachium nipponense

“…A previous study [ 52 ] reported that the haploid number of chromosomes in oriental river prawn is 52. Other Macrobrachium species with reported karyotype analysis include the giant freshwater prawn ( Macrobrachium rosenbergii ; n = 59) [ 53 ], Dimua river prawn ( Macrobrachium villosimanus ; n = 62) [ 54 ], Macrobrachium siwalikensis (n = 50) [ 55 ], Lachester freshwater prawn ( Macrobrachium lachesteri ; n = 58) [ 56 ], freshwater shrimp ( Macrobrachium carcinus ; n = 47) [ 57 ], Macrobrachium acanthurus (n = 49) [ 57 ], and Amazon river prawn ( Macrobrachium amazonicum ; n = 49) [ 57 ]. In the present study, a total of 49 chromosomes were assembled, which is close to the reported number of haploid chromosomes in the oriental river prawn.…”

The Pontastacus leptodactylus (Astacidae) Repeatome Provides Insight Into Genome Evolution and Reveals Remarkable Diversity of Satellite DNA

“…Large AT-rich probable HSs positioned in the (peri)centromeric position on all chromosomes and interstitially on some chromosomes suggest a high amount of repetitive DNA in the genome of P. leptodactylus (this study; Mlinarec et al, 2011 ). Large (peri)centromeric HSs have been found in different crustacean families such as Astacidae (Mlinarec et al, 2011 , 2016 ), Nephropidae (Deiana et al, 1996 ; Coluccia et al, 2001 ; Salvadori et al, 2002 ), Scyllaridae (Deiana et al, 2007 ), Palinuridae (Coluccia et al, 1999 , 2005 ; Cannas et al, 2004 ), Cambaridae (Salvadori et al, 2014 ), and Palaemonidae (González-Tizón et al, 2013 ; Torrecilla et al, 2017 ; Molina et al, 2020 ).…”

“…In the hermit crab Pagurus pollicaris , a minisatellite AGTGCAG(CTG) n constitutes a large fraction of its genome (Chambers et al, 1978 ). An exceptional abundance of microsatellite and SSR sequences has also been found in the genome of freshwater prawns of the genus Macrobrachium (Palaemonidae) as well as in the penaeid shrimp Litopenaeus vannamei (Zhang et al, 2019 ; Molina et al, 2020 ), suggesting that short tandem repeats are a significant component of decapod crustaceans genomes.…”

Multigene phylogeny and taxonomic revision of American shrimps of the genus Cryphiops Dana, 1852 (Decapoda, Palaemonidae) implies a proposal for reversal of precedence with Macrobrachium Spence Bate, 1868

“…The high diversity and worldwide tropical-subtropical distribution of Macrobrachium , combined with the scarcity of morphologic characters for accurate generic and specific delimitation, has long been intriguing taxonomists regarding its systematics, phylogenetic affinities, and biogeographic patterns. Several studies have been published on these topics using both morphological and molecular data, and, more recently, applying integrative approaches ( Pereira 1997 ; Bowles et al 2000 ; Murphy and Austin 2003 , 2005 ; Short 2004 ; Hernández et al 2007 ; Liu et al 2007 ; Valencia and Campos 2007 ; Wowor and Ng 2007 ; Parhi et al 2008 ; Wowor et al 2009 ; Pileggi and Mantelatto 2010 ; Acuña Gómez et al 2013 ; Rossi and Mantelatto 2013 ; Pileggi et al 2014 ; Jose et al 2016 ; Jose and Harikrishnan 2019 ; Mokambu et al 2019 ; Molina et al 2020 ). Among other factors, the high number of species has been hampering a comprehensive study on the phylogeny of the genus, but several articles were published on this at a regional level, either based on American (e.g., Pileggi and Mantelatto 2010 ; Acuña Gómez et al 2013 ; Rossi and Mantelatto 2013 ; Pileggi et al 2014 ), African (e.g., Mokambu et al 2019 ), or Indo-West Pacific species (e.g., Murphy and Austin 2005 ; Liu et al 2007 ; Parhi et al 2008 ; Chen et al 2009 ; Wowor et al 2009 ; Jose and Harikrishnan 2019 ; Siriwut et al 2020 ).…”