Large-scale development of gene-associated single-nucleotide polymorphism markers for molluscan population genomic, comparative genomic, and genome-wide association studies.

Mollusca is the second most diverse group of animals in the world. Despite their perceived importance, omics-level studies have seldom been applied to this group of animals largely due to a paucity of genomic resources. Here, we report the first large-scale gene-associated marker development and evaluation for a bivalve mollusc, Chlamys farreri. More than 21,000 putative single-nucleotide polymorphisms (SNPs) were identified from the C. farreri transcriptome. Primers and probes were designed and synthesized for 4500 SNPs, and 1492 polymorphic markers were successfully developed using a high-resolution melting genotyping platform. These markers are particularly suitable for population genomic analysis due to high polymorphism within and across populations, a low frequency of null alleles, and conformation to neutral expectations. Unexpectedly, high cross-species transferability was observed, suggesting that the transferable SNPs may largely represent ancestral genetic variations that have been preserved differentially among subfamilies of Pectinidae. Gene annotations were available for 73% of the markers, and 65% could be anchored to the recently released Pacific oyster genome. Large-scale association analysis revealed key candidate genes responsible for scallop growth regulation, and provided markers for further genetic improvement of C. farreri in breeding programmes.

[Effectiveness of radiofrequency ablation combined with transcatheter arterial chemoembolization for hepatocellular carcinoma].

OBJECTIVE: To analyze the short-term and long-term effectiveness of radiofrequency ablation (RFA) combined with transcatheter arterial chemoembolization (TACE) in the treatment of hepatocellular carcinoma (HCC). METHODS: The clinical data of 114 HCC patients, 104 males and 10 females, aged 55 (30 - 81), treated by RFA combined with TACE and followed up for 20 (1 - 82) months were analyzed. RESULTS: Complete necrosis was achieved in 101 patients (88.6%). 10 patients showed incomplete necrosis and 3 patients showed new neoplasm, and they all underwent repeated RFA or TACE. No therapy-relative death was found. The overall 1-, 2-, 3-, 4-, and 5-year survival rates were 90.4%, 82.6%, 73.2%, 63.5%, and 49.1%respectively. The 1-, 2-, 3-, 4-, and 5-year tumor progression-free survival rates were 77.1%, 64.6%, 54.6%, 46.8%, and 36.4% respectively. The overall 1-, 2-, 3-, 4-, and 5-year survival rates for the tumors with the size < or = 5 cm and the tumors with the size of 5.1 - 7 cm were 95.5%, 84.6%, 73.1%, 61.5%, and 50.6% and 80.2%, 64.9%, 56.3%, 45.3%, and 39.5% respectively (P = 0.041). The overall 1-, 2-, 3-, 4-, and 5-year survival rates for the solitary tumor and multiple tumors (no more than 3 tumors) were 95.8%, 89.1%, 78.1%, 67.1%, and 56.7% and 80.0%, 60.6%, 46.6%, 33.4%, and 21.5% respectively (P = 0.001). The levels of albumin and alpha-fetoprotein, and boundary and number of tumors were proved to be independent risk factors of survival. CONCLUSION: RFA combined with TACE is an effective treatment for HCC with satisfactory short-term and long-term effects, especially for the patients with tumor of the size of 5.1 - 7 cm or multiple lesions.