2013 Vol. 34, No. 5
Sarcocheilichthys nigripinnis is a small cyprinid fish widely distributed in East Asia, and it has been widely used in biogeographic analyses of freshwater fishes in China. In the present study, 142 S. nigripinnis individuals from 20 sampling sites in eight river systems were collected to investigate its phylogeography and genetic variations.. Populations from the Yellow River represent northern clade and all others represent southern clade. The results showed that 56 haplotypes were identified as mitochondrial DNA (mtDNA) Cyt b gene of 1 140 bp length. Relatively high haplotype diversity (h=0.971) and low nucleotide diversity (π=0.0212) were detected, and the estimated average genetic distance was 2.2%. Moreover, a neighbor-joining(NJ)tree revealed seven strongly supported lineages. Populations from the Yellow River were located at the basal position, whereas the remaining populations were more derived. Our results indicate that S. czerskii might have been evolved from S. nigripinnis in the Yellow River ~1.03 Ma. Based on the phylogeographical analysis of S. nigripinnis, we also suggest that vicariance, following mountain uplift and drainage isolation, plays an important role in producing evolutionary lineage differentiations. Moreover, molecular dating estimated that the divergence time of S. czerskii could be dated back to 0.95~3.92 Ma. Mismatch distribution analysis and neutrality tests also suggested the recent demographic expansions of S. nigripinnis populations, and that the effects of Pleistocene climatic changes could be a vital factor of the population dynamics of S. nigripinnis.
One general requirement of individual laboratory animals is that they have known genetic backgrounds. However, ensuring such genetic similarity is difficult, and can be facilitated by breeding a full strain for experimentation. To this end, the authors bred 34 full-sib families of amphioxus larvae/embryos. Due to the high mortality of the embryos and larvae, only seven full-sib families of juvenile amphioxus Branchiostoma japonicum were obtained. Among them, the highest and lowest survival ratios were 32.4% and 1.67%, respectively, whereas the shortest metamorphosis and longest larva duration were 24 d and 42 d, respectively. These results demonstrate the feasibility of establishing full-sib families of amphioxus, and provide fundamental data needed for the future breeding of amphioxus strains.
To understand the population status and behavioural features of wintering common cranes in the Yancheng Nature Reserve, two transects were established and population trends were monitored every month over five recent winters from 2008 to 2013. Wintering behaviours were also observed in order to explore the possible effects of family size and age on time budgets. Results indicated that the populations were stable with a range of 303 to 707 individuals. Negative effects of coastal developments were not found on the wintering population of common cranes, which might be related to their diets and preference for artificial wetland habitats. We found a significant effect of age on time budgets, with juveniles spending more time feeding and less time alerting, which might be related to the needs of body development and skill learning. Family size did not affect the time budgets of the cranes, which indicated that adults did not increase vigilance investment even when raising a larger family.
This study describes a new blind barbine fish species, Sinocyclocheilus anshuiensis sp. nov. discovered based on five specimens collected from a cave in Luolou town, Lingyun County, Guangxi, China, in June and July 2012. Sinocyclocheilus anshuiensis is distinguished from other species of Sinocyclocheilus by having the following combination of characteristics: dorsal fin with 7 branched rays, last unbranched dorsal-fin ray weak with serrations on posterior edge of its lower part; pelvic-fin origin anterior to dorsal-fin origin; dorsal profile of head sharply uplift, a forward flesh tuber present on frontal; body covered with scales, and lateral line with 34–38 scales, lateral line scales are as big as their neighbor scales; caudal peduncle with developed fresh crests.
Over the past few decades, Medaka (Oryzias latipes) has become a model animal in teleost species research due both to its short reproductive cycle and efficient proliferate capacity. Unfortunately, however, systematic data of its sexual differentiation and development have yet to be obtained. In the present study, we observed Medaka gonad development from the earliest recognizable stages through differentiation to maturation under a light microscope, after paraffin sectioning and hematoxylin-eosin staining. The results showed that among juveniles aged 5 to 10 days, the gonad located on the right side of the dorsal abdominal cavity and the germ cells was significantly larger than the surrounding somatic cells. Ten days after hatching, sexual differences between females and males became obvious, and germline cysts derived from oogonium division were present in the gonad. At 50 days after hatching, ovarian cavities and mature sperm were observed. Moreover, during the study we also observed the coexistence of two sexual characteristics during a male's development. Together, these observations fill current gaps in developmental and genetic biology that will allow a more efficient use of Medaka as an experimental model.
Morphological differences were found among specimens of Garra orientalis from Minjiang River, Pearl River, Red River and Hainan Island. To confirm whether the morphological differences among these geographical populations had reached the level of subspecies or species, seventy-two specimens of Garra orientalis were divided into four groups according to the four drainage areas stated above. Ten external morphological characteristics were observed. Thirteen frame characteristics and twenty-three general characteristics were measured and analyzed for multivariate morphometrics. In scatter plots of principal components, the specimens from Hainan Island were relatively concentrated on the scatter plots, but were not completely separated from the other three drainages. The samples from the other three drainages were completely mixed together. These results indicated that the specimens from the different drainages could not be distinguished by morphological comparison and morphometric analysis. Species or subspecies level differentiation of Garra orientalis among geographical populations could instead be studied by molecular biological methods in the future.
In this study,spectra analysis was conducted to investigate the sexual dichromatism and relationship between body color and quality of the red-eared slider turtle (Trachemys scripta). Visual modeling revealed that the differences of the hues of body colors' ultraviolet (UV) components between male and female were significant. Moreover, the visible(VIS)components of the hues of forelimbs were correlated with body qualities of male but not of female. Our results indicated that UV might act as a signal for sexual cognition in red-eared slider turtles, and female might evaluate male by the VIS components of the hues of forelimbs. These findings provided preliminary results and perspectives to the sexual dichromatism and sexual selection behaviors of red-eared slider turtles.
In the present study we used both cytogenetics (measurement of DNA content, detection of chromosome number, observation of gonadal development)and molecular genetics(microsatellite analysis)to analyze the biological characteristics of gynogenetic M. amblycephala, which werecreatedthrough gynogenesis induced via UV-irradiated E. ilishaeformis spermatozoa to fertilize M. amblycephala eggs. The maternal genome was duplicated by cold shock in 0~4℃ cold water to form a population of M. amblycephala with 48 chromosomes whose DNA content was identical to the diploid maternal parent. Morphologically, this group of gynogenetic M. amblycephala was similar to the control group. All gynogenetic M. amblycephala were female, and no males were found in any of the examined gynogenetic M. amblycephala, providing cytogenetic evidence that our gynogenetic M. amblycephala are type XY. At the same time, microsatellite analysis showed that 63 alleles were amplified in the three test groups of gynogenetic M. amblycephala. Overall, the population of gynogenetic M. amblycephala observed heterozygosity average, and the expected average was significantly lower than the parental averages, demonstrating that after generation gynogenesis the gene homozygosity of M. amblycephala was significantly higher than the ordinary bream and E. ilishaeformis, making it a pure line. The genetic proximity of gynogenetic M. amblycephala to M. amblycephala demonstrates that gynogenesis passes on maternal DNA. Gynogenetic groups developed in this study may provide good genetic material for future breeding projects of M. amblycephala.
Perinatal period and adolescence are critical for brain development, which is the biological basis of an individual's sexual orientation and sexual behavior. In this study, animals were divided into two groups and their sexual orientations were observed: one group experienced drug treatments during the perinatal period, and the other group was castrated at puberty. The results showed that estradiol treatment had no effect on mature male offspring's sexual orientations, but 9 days and 14 days of clomiphene citrate treatment significantly increased the chance of homosexuality and effeminized behavior. In addition, the sexual orientation of mature normal male offspring, which were castrated when they were 21 days old,was not significant different from the control animals. These findings suggest that the inhibition of perinatal estrogen activities could suppress individual male-typical responses, enhance female-typical responses and induce homosexual orientations. Moreover, the masculinizing effects of estrogen were more obvious during perinatal period than adolescence.
Diet compositions of alien clearhead icefish(Protosalanx hyalocranius)in Lake Xingkai were investigated monthly from June 2010 through January 2011. Protosalanx hyalocranius preyed mainly on cladoceran, copepoda, shrimp, and larvae or juvenile fish. In June, P. Hyalocranius were smaller than 60 mm standard length(SL), and their diets were composed of zooplankton only. In July, fish began to appear infrequently in the diet of P. Hyalocranius larger than 60 mm SL, and by August fish was occurring in the diets of P. hyalocranius larger than 80 mm, 100 mm in September, and 120 mm in October and thereafter, respectively. The increase in the minimum SL of P. hyalocranius preying on fish within a given season reflects changes in resource availability, largely attributed to the corresponding increase in prey fish size as seasons progress. Protosalanx hyalocranius and Hemiculter sp. were the dominant prey fish in the diets of P. hyalocranius.
In the present study, we examined the potential uses of Alizarin complexone and Alizarin red S to mark S. grahami larvae and juveniles. Individuals of different ages (6 days, 20 days, 90 days) were immersed in four concentrations of a solution of each chemical (50, 100, 150 and 200 mg/L) for different periods of time (4-36 h). Marked individuals were euthanized 4-27 days after immersion, and the lapillus was removed and used to determine mark quality. After marking with 50-150 mg/L ALC and ARS, violet marks were visible under normal light, and scarlet fluorescent marks were visible under 510-560 nm green light. The clear marks under normal light were recorded, and a 100% survival rate was guaranteed under the following conditions: 6 day old larvae immersed in 50 mg/L ALC or ARS for 8h; 20 day old larvae immersed in 50 mg/L ALC or 100 mg/L ARS for 24h; 90 day old juveniles immersed in 100mg/L ALC or 150 mg/L ARS for 24 h.
Two new Cypriniformes fish records from Yunnan Province, Carassioides acuminatus (collected from mainstream of Red River in Hekou County) and Hemimyzon pumilicorpora (collected from Gula River, Gula Town, Funing County, upper stream of the Pearl River drainage), were identified during fish specimen sorting at Kunming Institute of Zoology, Chinese Academy of Sciences. These two new records not only clarify the distribution patterns of the two species, but also enrich the knowledge of native fishes of Yunnan Province.
2013, 34(5): 507-508. doi: 10.11813/j.issn.0254-5853.2013.5.0507
A new bird species record, the Eurasian Blackcap (Sylvia atricapilla), was witnessed and subsequently recorded from 22 December 2012 to 9 January 2013, in Kashi (N39°28', E76°00', altitude 1 260 m), southwest Xinjiang, China.
Systematic reverse-engineering of functional genome architecture requires precise modifications of gene sequences and transcription levels. The development and application of transcription activator-like effectors(TALEs) has created a wealth of genome engineering possibilities. TALEs are a class of naturally occurring DNA-binding proteins found in the plant pathogen Xanthomonas species. The DNA-binding domain of each TALE typically consists of tandem 34-amino acid repeat modules rearranged according to a simple cipher to target new DNA sequences. Customized TALEs can be used for a wide variety of genome engineering applications, including transcriptional modulation and genome editing. Such "genome engineering" has now been established in human cells and a number of model organisms, thus opening the door to better understanding gene function in model organisms, improving traits in crop plants and treating human genetic disorders.
Kisspeptin, a key factor in the neuroendocrinological regulation of animal reproduction, is a peptide product encoded by kiss genes, which act as the natural ligand of GPR54. Over the last decade, multiple functional molecular forms of kisspeptin have been found in vertebrate species. In fish, the major molecular structural form is kisspeptin-10. The kisspeptin/GPR54 system has multiple important functions in reproduction. This review provides an overview of our current knowledge on kisspeptin and its role in regulating fish reproductive, including the distribution and location of kisspeptin neurons in the brain, the molecular polymorphism of fish kisspeptin, functional diversity, the molecular mechanism of fish reproductive regulation, and the molecular evolution of kisspeptin as well as the co-regulation of fish reproduction by kisspeptin and other functional molecules. Perspectives on the future of kisspeptin regulation in fish reproduction are also highlighted.