Role of Chromosome Changes in Crocodylus Evolution and Diversity

Srikulnath, Kornsorn,Thapana, Watcharaporn,Muangmai, Narongrit Korea Genome Organization 2015 Genomics & informatics Vol.13 No.4

The karyotypes of most species of crocodilians were studied using conventional and molecular cytogenetics. These provided an important contribution of chromosomal rearrangements for the evolutionary processes of Crocodylia and Sauropsida (birds and reptiles). The karyotypic features of crocodilians contain small diploid chromosome numbers (30~42), with little interspecific variation of the chromosome arm number (fundamental number) among crocodiles (56~60). This suggested that centric fusion and/or fission events occurred in the lineage, leading to crocodilian evolution and diversity. The chromosome numbers of Alligator, Caiman, Melanosuchus, Paleosuchus, Gavialis, Tomistoma, Mecistops, and Osteolaemus were stable within each genus, whereas those of Crocodylus (crocodylians) varied within the taxa. This agreed with molecular phylogeny that suggested a highly recent radiation of Crocodylus species. Karyotype analysis also suggests the direction of molecular phylogenetic placement among Crocodylus species and their migration from the Indo-Pacific to Africa and The New World. Crocodylus species originated from an ancestor in the Indo-Pacific around 9~16 million years ago (MYA) in the mid-Miocene, with a rapid radiation and dispersion into Africa 8~12 MYA. This was followed by a trans-Atlantic dispersion to the New World between 4~8 MYA in the Pliocene. The chromosomes provided a better understanding of crocodilian evolution and diversity, which will be useful for further study of the genome evolution in Crocodylia.

Role of Chromosome Changes in Crocodilian Evolution and Diversity

Kornsorn Srikulnath,Watcharaporn Thapana,Narongrit Muangmai 한국유전체학회 2015 Genomics & informatics Vol.13 No.4

The karyotypes of most species of crocodilians were studied using conventional and molecular cytogenetics. These provided an important contribution of chromosomal rearrangements for the evolutionary processes of Crocodylia and Sauropsida (birds and reptiles). The karyotypic features of crocodilians contain small diploid chromosome numbers (30∼42), with little interspecific variation of the chromosome arm number (fundamental number) among crocodiles (56∼60). This suggested that centric fusion and/or fission events occurred in the lineage, leading to crocodilian evolution and diversity. The chromosome numbers of Alligator, Caiman, Melanosuchus, Paleosuchus, Gavialis, Tomistoma, Mecistops, and Osteolaemus were stable within each genus, whereas those of Crocodylus (crocodylians) varied within the taxa. This agreed with molecular phylogeny that suggested a highly recent radiation ofcrocodilians. Karyotype analysis also suggests the direction of molecular phylogenetic placement among crocodilians and their migration from the Indo-Pacific to Africa and The New World. Crocodilians originated from an ancestor in the Indo-Pacific around 9∼16 million years ago (MYA) in the mid-Miocene, with a rapid radiation and dispersion into Africa 8∼12 MYA. This was followed by a trans-Atlantic dispersion to the New World between 4∼8 MYA in the Pliocene. The chromosomes provided a better understanding of crocodilian evolution and diversity, which will be useful for further study of the genome evolution in Crocodylia.

Phylogeographic patterns in cryptic Bostrychia tenella species (Rhodomelaceae, Rhodophyta) across the Thai-Malay Peninsula

Bulan, Jakaphan,Maneekat, Sinchai,Zuccarello, Giuseppe C.,Muangmai, Narongrit The Korean Society of Phycology 2022 ALGAE Vol.37 No.2

Genetic diversity and distribution patterns of marine macroalgae are increasingly being documented in Southeast Asia. These studies show that there can be significant levels of genetic diversity and isolation between populations on either side of the Thai-Malay Peninsula. Bostrychia tenellla is a common filamentous red seaweed in the region and the entity is represented by at least two cryptic species. Despite being highly diverse and widespread, genetic variation and population structure of this species complex remains understudied, especially around the Thai-Malay Peninsula. We analyzed genetic diversity and inferred the phylogeographic pattern of specimens identified as B. tenella using the plastid RuBisCo spacer from samples from the Andaman Sea and the Gulf of Thailand. Our genetic analysis confirmed the occurrence of the two cryptic B. tenella species (B and C) along both coasts. Cryptic species B was more common in the area and displayed higher genetic diversity than species C. Historical demographic analyses indicated a stable population for species B, but more recent population expansion for species C. Our analyses also revealed that both cryptic species from the Andaman Sea possessed higher genetic diversity than those of the Gulf of Thailand. We also detected moderate to high levels of gene flow and weak phylogeographic structure of cryptic species B between the two coasts. In contrast, phylogeographic analysis showed genetic differences between populations of both cryptic species within the Andaman Sea. Overall, these results suggest that cryptic B. tenella species around Thai-Malay Peninsula may have undergone different demography histories, and their patterns of genetic diversity and phylogeography were likely caused by geological history and regional sea surface current circulation in the area.

First record of the cyanobacterial genus Wilmottia (Coleofasciculaceae, Oscillatoriales) from the South Orkney Islands (Antarctica)

Radzi, Ranina,Merican, Faradina,Broady, Paul,Convey, Peter,Muangmai, Narongrit,Omar, Wan Maznah Wan,Lavoue, Sebastien The Korean Society of Phycology 2021 ALGAE Vol.36 No.2

Two cyanobacterial morphotypes isolated from Signy Island, South Orkney Islands, maritime Antarctica were characterised using a polyphasic approach combining morphological, cytological and molecular analyses. These analyses showed that the strains grouped with members of the genus Wilmottia. This genus currently includes three species, W. murrayi, W. stricta, and W. koreana. Both morphotypes analysed in this study were placed within the clade of W. murrayi. This clade showed a well-supported separation from Antarctic and New Zealand strains, as well as strains from other regions. W. murrayi was first described from Antarctica and is now known from several Antarctic regions. Confirmation of the occurrence of W. murrayi at Signy Island significantly extends its known distribution in Antarctica. In addition, a new combination, W. arthurensis, is suggested for Phormidium arthurensis.

Genetic insights: mapping sex-specific loci in Siamese cobra (Naja kaouthia) sheds light on the putative sex determining region

Jaito Wattanawan,Panthum Thitipong,Ahmad Syed Farhan,Singchat Worapong,Muangmai Narongrit,Han Kyudong,Koga Akihiko,Duengkae Prateep,Srikulnath Kornsorn 한국유전학회 2024 Genes & Genomics Vol.46 No.1

The location of female-specific/linked loci identified in Siamese cobra (Naja kaouthia) previously has been determined through in silico chromosome mapping of the Indian cobra genome (N. naja) as a reference genome. In the present study, we used in silico chromosome mapping to identify sex-specific and linked loci in Siamese cobra. Many sex-specific and sex-linked loci were successfully mapped on the Z sex chromosome, with 227 of the 475 specific loci frequently mapped in a region covering 57 Mb and positioned at 38,992,675–95,561,177 bp of the Indian cobra genome (N. naja). This suggested the existence of a putative sex-determining region (SDR), with one specific locus (PA100000600) homologous to the TOPBP1 gene. The involvement of TOPBP1 gene may lead to abnormal synaptonemal complexes and meiotic chromosomal defects, resulting in male infertility. These findings offer valuable insights into the genetic basis and functional aspects of sex-specific traits in the Siamese cobra, which will contribute to our understanding of snake genetics and evolutionary biology.

Disclosing the hidden nucleotide sequences: a journey into DNA barcoding of raptor species in public repositories

Jaito Wattanawan,Sonongbua Jumaporn,Panthum Thitipong,Wattanadilokcahtkun Pish,Ariyaraphong Nattakan,Thong Thanyapat,Singchat Worapong,Ahmad Syed Farhan,Kraichak Ekaphan,Muangmai Narongrit,Han Kyudong 한국유전학회 2024 Genes & Genomics Vol.46 No.1

Background In nucleotide public repositories, studies discovered data errors which resulted in incorrect species identification of several accipitrid raptors considered for conservation. Mislabeling, particularly in cases of cryptic species complexes and closely related species, which were identified based on morphological characteristics, was discovered. Prioritizing accurate species labeling, morphological taxonomy, and voucher documentation is crucial to rectify spurious data. Objective Our study aimed to identify an effective DNA barcoding tool that accurately reflects the efficiency status of barcodes in raptor species (Accipitridae). Methods Barcode sequences, including 889 sequences from the mitochondrial cytochrome c oxidase I (COI) gene and 1052 sequences from cytochrome b (Cytb), from 150 raptor species within the Accipitridae family were analyzed. Results The highest percentage of intraspecific nearest neighbors from the nearest neighbor test was 88.05% for COI and 95.00% for Cytb, suggesting that the Cytb gene is a more suitable marker for accurately identifying raptor species and can serve as a standard region for DNA barcoding. In both datasets, a positive barcoding gap representing the difference between inter-and intra-specific sequence divergences was observed. For COI and Cytb, the cut-off score sequence divergences for species identification were 4.00% and 3.00%, respectively. Conclusion Greater accuracy was demonstrated for the Cytb gene, making it the preferred primary DNA barcoding marker for raptors. Background In nucleotide public repositories, studies discovered data errors which resulted in incorrect species identification of several accipitrid raptors considered for conservation. Mislabeling, particularly in cases of cryptic species complexes and closely related species, which were identified based on morphological characteristics, was discovered. Prioritizing accurate species labeling, morphological taxonomy, and voucher documentation is crucial to rectify spurious data. Objective Our study aimed to identify an effective DNA barcoding tool that accurately reflects the efficiency status of barcodes in raptor species (Accipitridae). Methods Barcode sequences, including 889 sequences from the mitochondrial cytochrome c oxidase I (COI) gene and 1052 sequences from cytochrome b (Cytb), from 150 raptor species within the Accipitridae family were analyzed. Results The highest percentage of intraspecific nearest neighbors from the nearest neighbor test was 88.05% for COI and 95.00% for Cytb, suggesting that the Cytb gene is a more suitable marker for accurately identifying raptor species and can serve as a standard region for DNA barcoding. In both datasets, a positive barcoding gap representing the difference between inter-and intra-specific sequence divergences was observed. For COI and Cytb, the cut-off score sequence divergences for species identification were 4.00% and 3.00%, respectively. Conclusion Greater accuracy was demonstrated for the Cytb gene, making it the preferred primary DNA barcoding marker for raptors.

Quality control of fighting fish nucleotide sequences in public repositories reveals a dark matter of systematic taxonomic implication

Panthum Thitipong,Ariyaphong Nattakan,Wattanadilokchatkun Pish,Singchat Worapong,Ahmad Syed Farhan,Kraichak Ekaphan,Dokkaew Sahabhop,Muangmai Narongrit,Han Kyudong,Duengkae Prateep,Srikulnath Kornsorn 한국유전학회 2023 Genes & Genomics Vol.45 No.2

Background The number of nucleotide sequences in public repositories has exploded recently. However, the data contain errors, leading to incorrect species identification. Several fighting fish (Betta spp.) are poorly described, with unresolved cryptic species complexes masking undescribed species. Here, DNA barcoding was used to detect erroneous sequences in public repositories. Objective This study reflects the current quantitative and qualitative status of DNA barcoding in fighting fish and provides a rapid and reliable identification tool. Methods A total of 1034 barcode sequences were analyzed from mitochondrial cytochrome c oxidase I (COI) and cytochrome b (Cytb) genes from 71 fighting fish species. Results The nearest neighbor test showed the highest percentage of intraspecific nearest neighbors at 93.41% for COI and 91.67% for Cytb, which can be used as reference barcodes for certain taxa. Intraspecific variation was usually less than 13%, while most species differed by more than 54%. The barcoding gap, calculated from the difference between inter- and intraspecific sequence divergences, was negative in the COI data set indicating overlapping intra- and interspecific sequence divergence. Sequence saturation was observed in the Cytb data set but not in the COI data set. Conclusion The COI gene should thus be used as the main barcoding marker for fighting fish.