Productive Traits and Triploid Rate Stability in Triploidy-Induced ‘Haida No. 2’ Strain of the Pacific Oyster, Crassostrea gigas

In order to evaluate the effects of triploidy induction on a selected strain‘Haida No.2’of the Pacific oyster Crassostrea gigas,which is characterized with golden shell color and high growth rate,the growth,survival rate and stability of triploid rate were analyzed at different development stages in the present study.Three different conditions inhibiting the release of polar body Ⅱ or polar body Ⅰ were tested:(A)Cytochalasin-B(CB),0.5mg L^(−1) at 10min post-insemination for 15 min;(B)CB,0.5mg L^(−1)at 15 min postinsemination for 20 min;and(C)CB,0.7mg L^(−1),at 15 min post-insemination for 20 min.The triploidy induction treatments significantly reduced the D-larvae and survival rates at the larvae stage but not at the juvenile and adult stages.Triploid rate dramatically decreased at the larval stage and did not significantly change at the juvenile and adult stages.Regarding the stability of the triploid rate,there was a significant difference between the three treatment groups.Larvae from the treatment A and control groups exhibited higher growth rates in shell height than those from the other two treatment groups at day 27.Triploid juveniles and adults from the treatment A group exhibited a higher wet weight than diploids from the control group and triploids from the other treatment groups.Triploidy induction did not affect the shell color of the progeny.The results obtained in the study demonstrate that triploidy induction has the potential to be used to increase the production of C.gigas variety‘Haida No.2’without modifying its golden shell color.

AN EXPERIMENT ON INDUCTION OF TRIPLOIDY IN ERIOCHEIR JAPONICUS HEPUENSIS DAI BY HEAT TREATMENT

Temperature treatment to inhibit extrusion of the polar body of the egg was first used on a lower crustacean, Anemia salina (Gross, 1932), and then was used for inducing triploids of amphibian (Frankhauser and Griffiths, 1939), fish (Svardson, 1945), and mammal (Beatly and Fishchberg, 1949).So far, induction of triploidy has been extensively used to obtain sterile or quick-growth individuals in fish (Swarup, 1956; Lincoln.and Scott, 1983 and Thorgaard, 1986) and mollusk (Stanley et al., 1984), but similar work has not been reported on crab, a higher crustacean.

TRIPLOIDY INDUCTION WITH HEAT SHOCKS TO PENAEUS CHINENSIS AND THEIR EFFECTS ON GONAD DEVELOPMENT

Heat shocks effectively produced triploids in Penaeus chinensis . Fertilized eggs heat shocked (28-32℃) for 8 to 16 minutes, starting from 8 to 20 minutes after spawning, resulted in triploidy induction rates of 39%-75%. Several triploid populations were cultured to 10 cm. In a triploid population, two kinds of ovaries were observed. Histological examination showed apparent differences between these two kinds of ovaries, whereas among male shrimp, there were no such differences.

STUDY ON EMBRYONIC DEVELOPMENT AND EARLY GROWTH OF TRIPLOID AND GYNOGENETIC DIPLOID LEFT-EYED FLOUNDER, PARALICHTHYS OLIVACEUS (T. et S.)

The early effects of chromosomal manipulation of eggs and sperm on the yields of triploid and gynogenetic diploid larvae of Paralichthys olivaceus were investigated. Triploidy was achieved by cold shocking fertilized eggs at 0-2℃ for 45 minutes duration 5 minutes after fertilization, and the induced triploidy rates were 31.2%-50% and the relative hatching rates were 53.3%-99%. Gynogenetic diploids were obtained when eggs were inseminated with irradiated sperm and cold shocked at 0-2℃ for 45 minutes duration 5 minutes after fertilization. The induced gynogenetic diploid rates and the relative hatching rates were 94%-96% and 48.5%-68.5% respectively. The embryonic development of the triploid experimental group and of the gynogenetic diploid experimental group was delayed at first compared with the control group. But from the gastrula stage, it was not delayed anymore. There were no significant differences in the growth of the triploid experimental group larvae and the control group larvae, and in the growth of the gynogenetic diploid experimental group larvae and the control group larvae according to Student’s t test (α=0.05). The relationship between the early growth of the triploid experimental group larvae and that of gynogenetic diploid experimental group larvae was also studied.

Single Nucleotide Polymorphism-Based Chromosomal Microarray Evaluation of Hydatidiform Moles: A US National Reference Laboratory Experience

Objectives: This retrospective study evaluated 1) benefits of single nucleotide polymorphism (SNP)-based chromosomal microarrays (CMAs) in the diagnosis of complete hydatidiform mole (CHM) and partial HM (PHM) in products of conception (POC) and amniotic fluid (AF) specimens, and 2) frequency of whole-genome uniparental disomy (wgUPD) and triploidy in POC and AF specimens received at a US national reference laboratory. Methods: We reviewed consecutive 2138 POC and 3230 AF specimens and identified the cases with wgUPD and triploidy which are associated with molar pregnancy. Results: Of 2138 consecutive POC specimens tested, SNP-based CMA detected wgUPD in 10 (0.47%) and triploidy in 84 (3.93%). Of the 10 wgUPD cases, 9 (90%) were confirmed as CHM. Of 3230 consecutive AF specimens, the array detected wgUPD in 1 case (0.03%) and triploidy in 11 (0.34%). Conclusions: SNP-based microarray allows detection of wgUPD in POC and AF specimens at a US national reference laboratory. Correctly diagnosing HM and differentiating CHM from PHM are important for clinical management. The effective SNP-based CMA detection of wgUPD in CHM may enable physicians to monitor patients at risk for gestational trophoblastic disease and neoplasm. Conventional chromosome analysis of POC has a high failure rate, cannot be performed on formalin-fixed paraffin embedded samples, and cannot detect wgUPD. Further multi-institutional collaborative assessmen on accuracy, cost-effectiveness, and adequate access to SNP-based CMA, may lead this testing platform to be considered as the first-tier analysis tool for POC specimens, including those showing PHM or CHM.