First Analysis on the Cytogenetics of Painted Sweetlip, Plectorhinchus Pictus (Heamulidae: Perciformes) from Thailand
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© 2017 The Japan Mendel Society Cytologia 82(2): 145–150 First Analysis on the Cytogenetics of Painted Sweetlip, Plectorhinchus pictus (Heamulidae: Perciformes) from Thailand Sitthisak Jantarat1, Weerayuth Supiwong2*, Krit Phintong3, Khunapat Sonsrin3, Nipasak Kong-ngarm3 and Alongklod Tanomtong4 1 Biology Program, Department of Science, Faculty of Science and Technology, Prince of Songkla University, Pattani, Muang 94000, Thailand 2 Faculty of Applied Science and Engineering, Khon Kaen University, Nong Khai Campus, Nong Khai, Muang 43000, Thailand 3 Department of Fundamental Science, Faculty of Science and Technology, Surindra Rajabhat University, Surin, Muang 32000, Thailand 4 Toxic Substances in Livestock and Aquatic Animals Research Group, Department of Biology, Faculty of Science, Khon Kaen University, Khon Kaen, Muang 40002, Thailand Received April 25, 2016; accepted December 28, 2016 Summary Cytogenetic analysis of painted sweetlip (Plectorhinchus pictus) in Thailand was performed for the first time. The specimens were collected from Andaman Sea, Pluket Province, southern of Thailand. Chro- mosomes were prepared from kidney tissues followed by conventional staining and NOR banding techniques. The results showed that the diploid chromosome number of P. pictus is 2n=48, and the fundamental numbers (NF) are 48 in both sexes. The karyotype of this fish consisted of 30 large telocentric and 18 medium telocentric chromosomes. No differentiated sex chromosomes were observed. The region adjacent to the subcentromeric of the fifth telocentric chromosome pair presented clearly observable secondary constriction/NORs. The karyotype formula for P. pictus is as follows: tt 2n (48)=L30 +M 18 Key words Plectorhinchus pictus, Karyotype, Chromosome, Thailand. Thailand is one of the species diversity centers of the This species can reach 84 cm in total length (TL). It is a world. There are more than 2000 species of marine fish commercially important species and can be found in the having been recorded (Vidthayanon 2008). Marine fishes aquarium trade (Myers 1991). are especially important as they provide a high quality Of about 13000 marine fish species that have been re- source of protein as well as food source for people who corded (Nelson 2006), fewer than 5% of these have been live near the coast. Fishes in the Haemulidae family and studied cytogenetically (Arai 2011). Most marine fishes the order Perciformes are known commonly as grunts. studied have a diploid complement of 48 acrocentric There are about 135 species in 19 genera. Thus, Haemu- (telocentric) chromosomes (Sola et al. 1981, Klinkhardt lidae is one of the largest Perciformes families (Nelson et al. 1995, Brum 1996). There are only 18 species in 2006). In tropical regions, grunts are commercially and the family Haemulidae that have already been treated ecologically important (Nirchio et al. 2007). Plectorhin- on cytogenetic studies. Six different genera includ- chus is a genus of grunts, the sweetlips, found in fresh, ing Anisotremus, Conodon, Haemulon, Hapalogenys, brackish, and salt waters. These fish have big, fleshy lips and tend to live on coral reefs in the Indo-Pacific in small groups or pairs. They will often associate with other fishes of similar species; several species of sweet- lips sometimes swim together. They are usually seen in clusters in nooks and crannies or under overhangs (De- belius 2001). P. picus, the painted sweetlips (Fig. 1), is a species of grunt native to coral reefs of the Indian Ocean and the western Pacific Ocean at depths of 3 to 50 m. * Corresponding author, e-mail: [email protected] Fig. 1. General characteristics of the painted sweetlip (Plectorhin- DOI: 10.1508/cytologia.82.145 chus pictus). 146 S. Jantarat et al. Cytologia 82(2) Orthopristis and Pomadasys indicate that a basal karyo- Chromosome preparation was conducted by the squash type, with 2n=48 acrocentric chromosomes (NF=48), technique from kidney cells (Tanomtong et al. 2014). has been largely maintained (Brum et al. 1995, Yu The chromosomes were stained with 10% Giemsa’s for et al. 1995, Ron and Nirchio 2005, Galetti Jr. et al. 30 min and identified for NORs by Ag-NOR staining 2006, Nirchio et al. 2007, Motta Neto et al. 2011a, b, (Howell and Black 1980). The length of short arm (Ls) 2012, Arai 2011). This karyotype is also present in and long arm (Ll) chromosome were measured and most families of this order. Accordingly, to better deter- calculated for the length of total arm chromosome (LT, mine the degree of chromosomal conservatism present LT=Ls+Ll). Relative length (RL) and centromeric index in this family, a more detailed cytogenetic analysis of (CI) were estimated. CI was also computed to clas- species belonging to other Haemulidae genera, such as sify the types of chromosomes according to Chaiyasut Plectorhinchus should be performed. (1989). All parameters were used in karyotyping and The present study is aimed at cytogenetically analyz- idiograming. ing P. pictus. From the present study, we exhibit the standardization of karyotype and idiogram of P. pictus. Results and discussion This report describes the first chromosome staining by conventional staining and Ag-NOR staining techniques This is the first report on P. pictus cytogenetics in this fish. The results obtained can provide more cyto- knowledge. Our results revealed that 2n=48 of diploid genetic information for future studies on taxonomy and chromosome number is consistent to all species previ- evolutionary relationships of this family. Moreover, it ously studied in this family (Regan et al. 1968, Brum provides useful basic information for the conservation et al. 1995, Yu et al. 1995, Ron and Nirchio 2005, and breeding practices as well as the studies on chromo- Galetti Jr. et al. 2006, Nirchio et al. 2007, Motta Neto some evolution of this species. et al. 2011a, b, 2012 Arai 2011). P. pictus has NF=48 with 48 telocentric chromosomes (Fig. 2). It is the same Materials and methods as all species in the genera Anisotremus (Galetti Jr. et al. 2006, Nirchio et al. 2007), Conodon (Galetti Jr. et al. The P. pictus samples were obtained from Andaman 2006, Motta Neto et al. 2011b, 2012), Haemulon (Regan Sea, Pluket Province, Southern Thailand. The fish, five et al. 1968, Ron and Nirchio 2005, Galetti Jr. et al. 2006, males and five females of P. pictus, were transferred Nirchio et al. 2007, Motta Neto et al. 2011a, 2012, to laboratory aquaria and were kept under standard Arai 2011) and Pomadasys (Rishi and Haobam 1984, conditions for seven days prior to the experiments. Khuda-Bukhsh and Nayak 1990, Galetti Jr. et al. 2006, Fig. 2. Metaphase chromosome plates and karyotypes of male (up) and female (down) painted sweetlip (Plectorhinchus pictus), 2n=48 by conventional straining technique (scale bars 5 µm). There is no observation of strange sized chromosomes re- lated to sex. 2017 First Analysis on the Cytogenetics of Painted Sweetlip, Plectorhinchus pictus (Heamulidae: Perciformes) from Thailand 147 Nirchio et al. 2007, Motta Neto et al. 2011b, 2012). 2002). According to the result, interstitial NOR sites are However, it is different from the genera Hapalogenys located adjacent to the centromere of the fifth telocen- and Orthopristis which have NF=60–70 and NF=50, tric pair in both sexes, and NOR polymorphism can be respectively (Yu et al. 1995, Brum et al. 1995). The revealed in some specimens (Fig. 3). Interstitial NOR comparative cytogenetics data of the Heamulidae family positions in a single acrocentric (telocentric) pair were is presented in Table 1. observed, and given that they are also present in other Similar to other species in the family Haemulidae, Haemulidae species (Galetti Jr. et al. 2006, Nirchio et al. no strange sized chromosome related to sex was ob- 2007, Motta Neto et al. 2011a, b, 2012), they may rep- served in P. pictus. The karyotypes of P. pictus and most resent a conserved condition for this fish family, as well species of the family Haemulidae presenting 2n=48 as for others from the same order, such as Serranidae telocentric chromosomes (NF=48) indicate high con- (Aguilar and Galleti 1997), Sciaenidae (Feldberg et al. servation of chromosome feather in this family. These 1999) Lutjanidae (Rocha and Molina 2008) and Chae- karyotypes are regarded as a plesiomorphic trait for todontidae (Jumrusthanasan and Supiwong 2015). Perciformes (Galetti Jr. et al. 2000, Nirchio et al. 2007). This condition may result in a decreased evolution- Moreover, they possibly represent a synapomorphy for ary dynamism of these sites (Nirchio et al. 2007), Clupeomorpha and Euteleostei (Brum and Galetti Jr. accounting for their stability in many Perciformes spe- 1997, Nirchio et al. 2007). cies. However, the NOR-bearing chromosome pair in The present study, the first cytogenetic report of P. pictus is distinct from other genera. Anisotremus and P. pictus, was accomplished using the Ag-NOR staining Pomadasys (P. corvinaeformis) were observed in the technique. The objective of this technique is to identify pair 18 (Galetti Jr. et al. 2006, Nirchio et al. 2007, Motta the nucleolar organizer regions (NORs), which represent Neto et al. 2011b, 2012) whereas Conodon (C. nobilis) the location of genes (loci) that function in ribosome and Haemulon were found in pair 24 (Ron and Nirchio synthesis (18S and 28S ribosomal RNA) (Sharma et al. 2005, Galetti Jr. et al. 2006, Nirchio et al. 2007, Motta Table 1. Cytogenetic reports in the family Heamulidae. Species 2n Karyotype formula NF NOR banded Reference Anisotremus moricandi 48 48t 48 2 Galetti Jr. et al. (2006) 48 48t 48 2 Nirchio et al. (2007) A. surinamensis 48 48t 48 2 Galetti Jr. et al. (2006) 48 48t 48 2 Nirchio et al. (2007) A. virginicus 48 48t 48 2 Galetti Jr. et al. (2006) 48 48t 48 2 Nirchio et al. (2007) Conodon nobilis 48 48t 48 ̶ Galetti Jr. et al. (2006) 48 48t 48 2 Motta Neto et al.