Construction of Genetic Linkage Maps From a Hybrid Family of Large Yellow Croaker (Larimichthys crocea)

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Genetic diversity and population structure of Sepiella japonica (Mollusca: Cephalopoda: Decapoda) inferred by 16S rDNA variations

In order to describe the genetic diversity and phylogenetic relationship of five populations of cuttlefish (Sepiella japonica) along with China's coasts, partial 16S rDNA (510 bp in length) was amplified from 110 individuals. The five populations of cuttlefish inhabit Yellow Sea, East China Sea and South China Sea. In total, six haplotypes were identified and formed only one clade. Among the six haplotypes, one was shared by all populations, three appeared only in a single population, two appeared in two or three populations. Pair-wise FST were not proportional to the geographical distances. Haplotype diversity and nucleotide diversity were low, 0.3866 ± 0.067 and 0.00120 ± 0.00081 respectively. Among the five populations, Zhoushan population exhibited the highest genetic diversity which was suggested as the better select of germplasm resources for the reproduction and releasing of S. japonica

Construction of Genetic Linkage Maps From a Hybrid Family of Large Yellow Croaker (Larimichthys crocea)

Consensus and sex-specific genetic linkage maps for large yellow croaker (Larimichthys crocea) were constructed using samples from an F(1) family produced by crossing a Daiqu female and a Mindong male. A total of 20,147 single nucleotide polymorphisms (SNPs) by restriction site associated DNA sequencing were assigned to 24 linkage groups (LGs). The total length of the consensus map was 1757.4 centimorgan (cM) with an average marker interval of 0.09 cM. The total length of female and male linkage map was 1533.1 cM and 1279.2 cM, respectively. The average female-to-male map length ratio was 1.2 ± 0.23. Collapsed markers in the genetic maps were re-ordered according to their relative positions in the ASM435267v1 genome assembly to produce integrated genetic linkage maps with 9885 SNPs distributed across the 24 LGs. The recombination pattern of most LGs showed sigmoidal patterns of recombination, with higher recombination in the middle and suppressed recombination at both ends, which corresponds with the presence of sub-telocentric and acrocentric chromosomes in the species. The average recombination rate in the integrated female and male maps was respectively 3.55 cM/Mb and 3.05 cM/Mb. In most LGs, higher recombination rates were found in the integrated female map, compared to the male map, except in LG12, LG16, LG21, LG22, and LG24. Recombination rate profiles within each LG differed between the male and the female, with distinct regions indicating potential recombination hotspots. Separate quantitative trait loci (QTL) and association analyses for growth related traits in 6 months fish were performed, however, no significant QTL was detected. The study indicates that there may be genetic differences between the two strains, which may have implications for the application of DNA-information in the further breeding schemes

Cloning, expression pattern and promoter functional analysis of cyp19a1a gene in miiuy croaker

Gonadal-specific aromatase encoded by cyp19a1a is the important enzyme controlling estrogen biosynthesis in teleosts. In the present study, the cDNA sequence of cyp19a1a was cloned and characterized from miiuy croaker Miichthys miiuy. The cDNA encoded a protein of 519 amino acids with five structural regions. Higher identities of amino acid sequences and conserved structural regions were found between Mmcyp19a1a and other cyp19a1a genes. In addition, Mmcyp19a1a was clustered together with other seawater fishes. Immunohistochemical analysis revealed that Mmcyp19a1a was localized exclusively in the cytoplasmic of thecal and granulosa cells surrounding the oocytes. Both the protein and mRNA levels of Mmcyp19a1a were increased significantly at the stage III follicles (mid-vitellogenic) and then decreased along with vitellogenesis. Interestingly, strong immunoreactive signals were also detected in the supporting cells of connective tissues during ovarian development. A 1777 bp promoter fragment of Mmcyp19a1a was also isolated, and functional analysis using an EGFP reporter fusion in zebrafish larvae presented positive signals in the above of yolk sac, where is the region of pronephros and germ plasm occur. The Mmcyp19a1a:EGFP expression pattern was generally consistent with the endogenous cyp19a1a genesis. These results indicate that the Mmcyp19a1a gene plays an important role during vitellogenesis and oocyte maturation. The constructor of Mmcyp19a1a:EGFP may provide a useful tool for genetic analysis of gonad development in teleost.</p

Influence of parameters of high-energy ball milling on the synthesis and densification of magnesium aluminate spinel

This study investigated the effect of planetary ball mill parameters on the particle size of a powder mixture of alumina and magnesia, the composition of synthetic magnesium aluminate spinel (MAS), and the subsequent densification of MAS. The results show that the particle size of the milled powders decreases gradually from 32.39 μm to 11.69 μm with the increase of milling time from 1 h to 7 h at milling speed of 120 rpm. The particle size of the milled powders decreases gradually from 42.92 μm to 9.00 μm as the milling speed was increased from 60 rpm to 240 rpm at a milling time of 3 h. Only a spinel phase can be obtained from these calcined powders when the starting powders of the calcined powders are milled for more than 1 hour or at above 60 rpm. The relative density and flexural strength of the sintered products exceed 86.67% and 105 MPa, respectively

Data from: Chromosomal level reference genome of Tachypleus tridentatus provides insights into evolution and adaptation of horseshoe crabs

Horseshoe crabs including Tachypleus tridentatus are a group of marine arthropods living fossil species which have existed on the earth for 500 million years. However, the genetic mechanisms underlying their unique adaptive ability are still unclear. Here, we assembled the first chromosome-level T. tridentatus genome, and proofed that this genome is of very high quality with contig N50 1.69 Mb. By comparison with other arthropods, some gene families of T. tridentatus experienced significant expansion, whichare related to several signaling pathways, endonuclease activity, and metabolic processes. Based on the comparative analysis of genomics and 27 transcriptomes from 9 tissues, we found that the expanded Dscam genes usually locate at the key hub positions of immune network. Furthermore, the Dscam genes showed higher levels of expression in the yellow connective tissue, the birthplace of blood cells with strong differentiation capability, than the other 8 tissues. Besides, Dscam genes are positively correlated with the expression of the core immunity gene, clotting factor B, which is implicated in the coagulation cascade reaction. The effective and unusual immune ability endowed by the expansion and expression of Dscam genes in horseshoe crabs may be a factor that makes horseshoe crabs having a strong environmental adaptability with ~500 million years. The high-quality chromosome-level genome of a horseshoe crab and unique genomic features reported in this study provide important data resources for future studies on the evolutionary history of marine ecological systems

Mixtures of lupin and pea protein concentrates can efficiently replace high-quality fish meal in extruded diets for juvenile black sea bream (Acanthopagrus schlegeli)

A 60-day feeding experiment was carried out to investigate the effects of including lupin protein concentrate (LPC) and pea protein concentrate (PPC) in multiple essential amino acid-supplemented extruded diets for black sea bream (Acanthopagrus schlegeli). Nine diets, including eight diets formulated to contain four mixtures of LPC and PPC (L/P ratio, 3:0, 2:1, 1:2 and 0:3) with two dietary inclusion levels (300 or 500 g plant protein kg(-1) dietary protein) and one diet with high-quality fish meal as the sole protein source (FM diet) were fed to 18 tanks of 13-g black sea bream. Growth performance, nutrient utilization, and brush-border membrane bound maltase activities were evaluated. An average weight gain (WG) of 32.7 g fish(-1) and an average feed conversion ratio (FCR) of 1.13 g ingested dry matter (g gain)(-1) were obtained. Neither plant protein inclusion level nor L/P ratio significantly affected body composition (except ash), fish somatic indices or plasma parameters. The high inclusion of 500 g kg(-1) resulted in significantly higher FCR than what was obtained with 300 g kg(-1) inclusion. The WG, whole body ash content, and nitrogen (N) and energy retentions of these fish were, however, significantly lower than that of the fish fed diets with low plant protein inclusion (300 g kg(-1)). The highest LPC inclusion (L/P ratio = 3: 0) resulted in significantly higher feed intake and FCR, and lower N retention than the treatments with less LPC, but did not affect the growth rates or energy retentions. The diet with the highest PPC inclusion resulted in significantly reduced maltase activity in distal intestine. Any combination of LPC and PPC in essential amino acid-supplemented extruded diets, accounting for up to half of dietary protein, can be used without impairing fish growth. At high inclusion, combinations with more PPC are preferred, due to less efficient feed conversion caused by the LPC. (C) 2012 Elsevier B.V. All rights reserved.A 60-day feeding experiment was carried out to investigate the effects of including lupin protein concentrate (LPC) and pea protein concentrate (PPC) in multiple essential amino acid-supplemented extruded diets for black sea bream (Acanthopagrus schlegeli). Nine diets, including eight diets formulated to contain four mixtures of LPC and PPC (L/P ratio, 3:0, 2:1, 1:2 and 0:3) with two dietary inclusion levels (300 or 500 g plant protein kg(-1) dietary protein) and one diet with high-quality fish meal as the sole protein source (FM diet) were fed to 18 tanks of 13-g black sea bream. Growth performance, nutrient utilization, and brush-border membrane bound maltase activities were evaluated. An average weight gain (WG) of 32.7 g fish(-1) and an average feed conversion ratio (FCR) of 1.13 g ingested dry matter (g gain)(-1) were obtained. Neither plant protein inclusion level nor L/P ratio significantly affected body composition (except ash), fish somatic indices or plasma parameters. The high inclusion of 500 g kg(-1) resulted in significantly higher FCR than what was obtained with 300 g kg(-1) inclusion. The WG, whole body ash content, and nitrogen (N) and energy retentions of these fish were, however, significantly lower than that of the fish fed diets with low plant protein inclusion (300 g kg(-1)). The highest LPC inclusion (L/P ratio = 3: 0) resulted in significantly higher feed intake and FCR, and lower N retention than the treatments with less LPC, but did not affect the growth rates or energy retentions. The diet with the highest PPC inclusion resulted in significantly reduced maltase activity in distal intestine. Any combination of LPC and PPC in essential amino acid-supplemented extruded diets, accounting for up to half of dietary protein, can be used without impairing fish growth. At high inclusion, combinations with more PPC are preferred, due to less efficient feed conversion caused by the LPC. (C) 2012 Elsevier B.V. All rights reserved

Ttri_genome.fa.tar.gz

The genome file of horseshoe crab

Ttri_cds.tar.gz

The CDS sequence file of horseshoe crab