Crescimento relativo de Macrobrachium acanthurus (Wiegmann, 1836) (Crustacea, Decapoda, Palaemonidae)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Fecundidade em Macrobrachium acanthurus (Wiegmann, 1836) do Rio Ribeira de Iguape (Crustacea, Decapoda, Palaemonidae)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Maturation and growth curves of Macrobrachium Carcinus (Linnaeus) (Crustacea, Decapoda, Palaemonidae) from Ribeira de Iguape River, southern Brazil

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Efeito da densidade populacional sobre as curvas de crescimento de Macrobrachium rosenbergii (De Man) em cultivo semi-intensivo (Crustacea, Palaemonidae)

In this article the length growth curves of Macrobrachium rosenbergii (De Man, 1879) held in different population densities were analysed. Postlarvae prawns were stocked into five 0,02 ha earthen ponds at densities of 4, 8, 12, 16 and 20 ind./m² during six months. Forthnightly, the mean total length of animals from each pond were obtained by means of random samples. For each population the length growth curves and the instantaneous growth rate expressions were determined. The growth rate and the asymptotic maximum length decreased with the stocking density raised. This effect is greater when the density ranges in low levels. The growth decrease can be due to intraspecific competition for life resources and to negative interactions between individuals, as aggressive or social behavior, that increase with the increase prawns density.

Tm3+ and Tm3+-Ho3+ doped fluorogermanate glasses for S-band amplifiers

Two series of glasses with composition (mol%) 70PbGeO3- 15PbF2-15CdF2, the first one with different Tm 3+ contents (0.2, 0.4, 0.6 and 0.8 mol%) and the second one with 0.2 mol% Tm3+ and different Ho3+ contents (0.1, 0.5, 1.0 and 1.5 mol%), have been prepared and some of their spectroscopic properties studied. Absorption in the visible-near infrared and emission in the near infrared region of the electromagnetic spectrum have been obtained. Concerning emission at the 1.4-1.5 μm region, optimization of rare earth ions content leads to 0.2 and 0.5 mol% for Tm3+ and Ho3+, respectively. We discuss potential application of these compositions. © 2005 Elsevier B.V. All rights reserved.

Genome-Wide Analysis Reveals Selection for Important Traits in Domestic Horse Breeds

Intense selective pressures applied over short evolutionary time have resulted in homogeneity within, but substantial variation among, horse breeds. Utilizing this population structure, 744 individuals from 33 breeds, and a 54,000 SNP genotyping array, breed-specific targets of selection were identified using an FST-based statistic calculated in 500-kb windows across the genome. A 5.5-Mb region of ECA18, in which the myostatin (MSTN) gene was centered, contained the highest signature of selection in both the Paint and Quarter Horse. Gene sequencing and histological analysis of gluteal muscle biopsies showed a promoter variant and intronic SNP of MSTN were each significantly associated with higher Type 2B and lower Type 1 muscle fiber proportions in the Quarter Horse, demonstrating a functional consequence of selection at this locus. Signatures of selection on ECA23 in all gaited breeds in the sample led to the identification of a shared, 186-kb haplotype including two doublesex related mab transcription factor genes (DMRT2 and 3). The recent identification of a DMRT3 mutation within this haplotype, which appears necessary for the ability to perform alternative gaits, provides further evidence for selection at this locus. Finally, putative loci for the determination of size were identified in the draft breeds and the Miniature horse on ECA11, as well as when signatures of selection surrounding candidate genes at other loci were examined. This work provides further evidence of the importance of MSTN in racing breeds, provides strong evidence for selection upon gait and size, and illustrates the potential for population-based techniques to find genomic regions driving important phenotypes in the modern horse. © 2013 Petersen et al.

Genetic Diversity in the Modern Horse Illustrated from Genome-Wide SNP Data

Horses were domesticated from the Eurasian steppes 5,000-6,000 years ago. Since then, the use of horses for transportation, warfare, and agriculture, as well as selection for desired traits and fitness, has resulted in diverse populations distributed across the world, many of which have become or are in the process of becoming formally organized into closed, breeding populations (breeds). This report describes the use of a genome-wide set of autosomal SNPs and 814 horses from 36 breeds to provide the first detailed description of equine breed diversity. FST calculations, parsimony, and distance analysis demonstrated relationships among the breeds that largely reflect geographic origins and known breed histories. Low levels of population divergence were observed between breeds that are relatively early on in the process of breed development, and between those with high levels of within-breed diversity, whether due to large population size, ongoing outcrossing, or large within-breed phenotypic diversity. Populations with low within-breed diversity included those which have experienced population bottlenecks, have been under intense selective pressure, or are closed populations with long breed histories. These results provide new insights into the relationships among and the diversity within breeds of horses. In addition these results will facilitate future genome-wide association studies and investigations into genomic targets of selection. © 2013 Petersen et al.