Biology subjects

Cheung, S. G.

Publications and source records attributed to Cheung, S. G..

9 recordsLinked to original sources

bioRxiv2024

Genomes of two indigenous clams Anomalocardia flexuosa (Linnaeus, 1767) and Meretrix petechialis (Lamarck, 1818)

Clam digging has a long history in Hong Kong, but unregulated clam digging activities depletes clam populations and threatens the ecosystem. Population genomics is useful to unravel the connectivity of clams at different geographical locations and to provide necessary conservation measures; and yet, only limited number of clams in Hong Kong have genomic resources. Here, we present chromosomal-level genome assemblies for two clams commonly found in Hong Kong, Anomalocardia flexuosa and Meretrix petechialis, using a combination of PacBio HiFi and Omni-C reads. We assembled each genome ([~]1.04-1.09 Gb) into 19 pseudochromosomes with high sequence continuity (scaffold N50 = 58.5 Mb and 53.5 Mb) and high completeness (BUSCO scores 94.4% and 95.7%). A total of 20,881 and 20,084 gene models were also predicted for A. flexuosa and M. petechialis respectively using transcriptomes generated in this study. The two new genomic resources established in this study will be useful for further study of the biology, ecology, and evolution of clams, as well as setting up a foundation for evidence-informed decision making in conservation measures and implementation.

genomics↗

bioRxiv2024

Chromosomal-level genome assembly and single-nucleotide polymorphism sites of black-faced spoonbill Platalea minor

Platalea minor, the black-faced spoonbill (Threskiornithidae) is a wading bird that is confined to coastal areas in East Asia. Due to habitat destruction, it has been classified by The International Union for Conservation of Nature (IUCN) as globally endangered species. Nevertheless, the lack of its genomic resources hinders our understanding of their biology, diversity, as well as carrying out conservation measures based on genetic information or markers. Here, we report the first chromosomal-level genome assembly of P. minor using a combination of PacBio SMRT and Omni-C scaffolding technologies. The assembled genome (1.24 Gb) contains 95.33% of the sequences anchored to 31 pseudomolecules. The genome assembly also has high sequence continuity with scaffold length N50 = 53 Mb. A total of 18,780 protein-coding genes were predicted, and high BUSCO score completeness (93.7% of BUSCO metazoa_odb10 genes) was also revealed. A total of 6,155,417 bi-allelic SNPs were also revealed from 13 P. minor individuals, accounting for [~]5% of the genome. The resource generated in this study offers the new opportunity for studying the black-faced spoonbill, as well as carrying out conservation measures of this ecologically important spoonbill species.

genomics↗

bioRxiv2024

Genome assembly of the edible jelly fungus Dacryopinax spathularia (Dacrymycetaceae)

The edible jelly fungus Dacryopinax spathularia (Dacrymycetaceae) is wood-decaying and can be commonly found worldwide. It has also been used in food additives given its ability to synthesize long-chain glycolipids. In this study, we present the genome assembly of D. spathularia using a combination of PacBio HiFi reads and Omni-C data. The genome size of D. spathularia is 29.2 Mb and in high sequence contiguity and completeness, including scaffold N50 of 1.925 Mb and 92.0% BUSCO score, respectively. A total of 11,510 protein-coding genes, and 474.7 kb repeats accounting for 1.62% of the genome, were also predicted. The D. spathularia genome assembly generated in this study provides a valuable resource for understanding their ecology such as wood decaying capability, evolutionary relationships with other fungus, as well as their unique biology and applications in the food industry.

genomics↗

bioRxiv2024

Chromosomal-level genome assembly of the long-spined sea urchin Diadema setosum (Leske, 1778)

The long-spined sea urchin Diadema setosum is an algal and coral feeder widely distributed in the Indo-Pacific and can cause severe bioerosion on the reef community. Nevertheless, the lack of genomic information has hindered the study its ecology and evolution. Here, we report the chromosomal-level genome (885.8 Mb) of the long-spined sea urchin D. setosum using a combination of PacBio long-read sequencing and Omni-C scaffolding technology. The assembled genome contained scaffold N50 length of 38.3 Mb, 98.1 % of BUSCO (Geno, metazoa_odb10) genes, and with 98.6% of the sequences anchored to 22 pseudo-molecules/chromosomes. A total of 27,478 genes including 23,030 protein-coding genes were annotated. The high-quality genome of D. setosum presented here provides a significant resource for further understanding on the ecological and evolutionary studies of this coral reef associated sea urchin.

genomics↗

bioRxiv2024

Genome assembly of the rare and endangered Grantham's camellia, Camellia granthamiana

The Granthams camellia (Camellia granthamiana Sealy) is a rare and endangered tea species that is endemic to southern China, and was first discovered in Hong Kong in 1955. Despite its high conservation value, genomic resources of C. granthamiana remain limited. Here, we present a chromosome-scale draft genome of the tetraploid C. granthamiana (2n = 4x = 60) using a combination of PacBio long read sequencing and Omni-C data. The assembled genome size is [~]2.4 Gb with most sequences anchored to 15 pseudochromosomes that resemble a monoploid genome. The genome is of high contiguity, with a scaffold N50 of 139.7 Mb, and high completeness with a 97.8% BUSCO score. Gene model prediction resulted in a total 76,992 protein-coding genes with a BUSCO score of 85.9%. 1.65 Gb of repeat content was annotated, which accounts for 68.48% of the genome. The Granthams camellia genome assembly provides a valuable resource for future investigations on its biology, ecology, phylogenomic relationships with other Camellia species, as well as set up a foundation for further conservation measures.

plant biology↗

bioRxiv2024

Chromosome-level genome assembly of the common chiton, Liolophura japonica (Lischke, 1873)

Chitons (Polyplacophora) are marine molluscs that can be found worldwide from cold waters to the tropics, and play important ecological roles in the environment. Nevertheless, there remains only two chiton genomes sequenced to date. The chiton Liolophura japonica (Lischke, 1873) is one of the most abundant polyplacophorans found throughout East Asia. Our PacBio HiFi reads and Omni-C sequencing data resulted in a high-quality near chromosome-level genome assembly of [~]609 Mb with a scaffold N50 length of 37.34 Mb (96.1% BUSCO). A total of 28,233 genes were predicted, including 28,010 protein-coding genes. The repeat content (27.89%) was similar to the other Chitonidae species and approximately three times lower than in the genome of the Hanleyidae chiton. The genomic resources provided in this work will help to expand our understanding of the evolution of molluscs and the ecological adaptation of chitons.

genomics↗

bioRxiv2024

Genome assembly of the milky mangrove Excoecaria agallocha

The milky mangrove Excoecaria agallocha is a latex-secreting mangrove that are distributed in tropical and subtropical regions. While its poisonous latex is regarded as a potential source of phytochemicals for biomedical applications, the genomic resources of E. agallocha remains limited. Here, we present a chromosomal level genome of E. agallocha, assembled from the combination of PacBio long-read sequencing and Omni-C data. The resulting assembly size is 1,332.45 Mb and has high contiguity and completeness with a scaffold N50 of 58.9 Mb and a BUSCO score of 98.4 %. 73,740 protein-coding genes were also predicted. The milky mangrove genome provides a useful resource for further understanding the biosynthesis of phytochemical compounds in E. agallocha.

genomics↗

bioRxiv2024

Chromosomal-level genome assembly of golden birdwing Troides aeacus (Felder & Felder, 1860)

Troides aeacus, the golden birdwing (Lepidoptera, Papilionidae) is a large swallowtail butterfly widely distributed in Asia. Despite its occurrence, T. aeacus has been assigned as a major protective species in many places given the loss of their native habitats under urbanisation and anthropogenic activities. Nevertheless, the lack of its genomic resources hinders our understanding of their biology, diversity, as well as carrying out conservation measures based on genetic information or markers. Here, we report the first chromosomal-level genome assembly of T. aeacus using a combination of PacBio SMRT and Omni-C scaffolding technologies. The assembled genome (351 Mb) contains 98.94% of the sequences anchored to 30 pseudo-molecules. The genome assembly also has high sequence continuity with scaffold length N50 = 12.2 Mb. A total of 28,749 protein-coding genes were predicted, and high BUSCO score completeness (98.9% of BUSCO metazoa_odb10 genes) was also revealed. This high-quality genome offers a new and significant resource for understanding the swallowtail butterfly biology, as well as carrying out conservation measures of this ecologically important lepidopteran species.

genomics↗

bioRxiv2020

Horseshoe crab genomes reveal the evolutionary fates of genes and microRNAs after three rounds (3R) of whole genome duplication

Whole genome duplication (WGD) has occurred in relatively few sexually reproducing invertebrates. Consequently, the WGD that occurred in the common ancestor of horseshoe crabs ~135 million years ago provides a rare opportunity to decipher the evolutionary consequences of a duplicated invertebrate genome. Here, we present a high-quality genome assembly for the mangrove horseshoe crab Carcinoscorpius rotundicauda (1.7Gb, N50 = 90.2Mb, with 89.8% sequences anchored to 16 pseudomolecules, 2n = 32), and a resequenced genome of the tri-spine horseshoe crab Tachypleus tridentatus (1.7Gb, N50 = 109.7Mb). Analyses of gene families, microRNAs, and synteny show that horseshoe crabs have undergone three rounds (3R) of WGD, and that these WGD events are shared with spiders. Comparison of the genomes of C. rotundicauda and T. tridentatus populations from several geographic locations further elucidates the diverse fates of both coding and noncoding genes. Together, the present study represents a cornerstone for a better understanding of the consequences of invertebrate WGD events on evolutionary fates of genes and microRNAs at individual and population levels, and highlights the genetic diversity with practical values for breeding programs and conservation of horseshoe crabs.

evolutionary biology↗