Late flowering in F 1 hybrid rice brought about by the complementary effect of quantitative trait loci Abstract Late flowering sometimes occurs in F1 hybrids between rice varieties (Oryza sativa L.), although the parental varieties show similar days-to-flowering (DTF). The genetic architecture prompting the occurrence of such late flowering is poorly understood. To clarify the genetic architecture of late flowering in F1 hybrids from a cross between rice varieties, ‘Koshihikari’ and ‘IR64’, we performed quantitative trait locus (QTL) analysis using an F2 population (selfed progeny of an F1 plant), in which heterozygous genotypes should segregate in a certain proportion in a Mendelian manner. The QTL analysis detected three significant QTLs. At one QTL (putatively Heading date 1), the ‘Koshihikari’ allele increased DTF, and at the other two QTLs (putatively Heading date 6 and Oryza sativa Pseudo-Response Regulator 37/Heading date 2), the ‘IR64’ alleles increased DTF. All alleles at these three QTLs showed partial dominance. The combination of the QTLs explained 82.2% of the total phenotypic variance of DTF in the F2 population, with contribution from epistasis between QTLs. There was no difference between DTFs of F1 hybrids and heterozygous genotypes for the three QTLs. Our results demonstrated that the complementary effects accompanied by epistasis of at least three QTLs were responsible for late flowering in F1 hybrids.

Inferring boundaries among fish species of the new world silversides (Atherinopsidae; genus Odontesthes ): new evidences of incipient speciation between marine and brackish populations of Odontesthes argentinensis Abstract Species of new world silversides (Actinopterygii; Atherinopsidae; genus Odontesthes) possess economic relevance, biological interest and ecological importance. In the present paper we: (A) investigate the molecular diversity in marine species of Odontesthesfrom the South West Atlantic Ocean (SWAO), and analyse their interspecific relationships and divergence by means of DNA Barcoding, including its freshwater congeners, as well. (B) Explore the suitability of DNA Barcoding to analyse the diversity and distribution of haplotypes in Odontesthes argentinensis, the only well documented marine species from the SWAO that exhibit putative estuarine and marine populations. Molecular analysis revealed 100% of agreement between morphological identification and molecular identity. Odontesthes argentinensis, Odontesthes platensis, Odontesthes smitti, Odontesthes nigricans and Odontesthes incisa were assigned to five different barcode index numbers (BINs). Maximum-likelihood analysis showed that all marine species of Odontesthes clustered separately in a unique monophyletic phylogroup, comprising five well defined haplogroups, with genetic divergence between groups ranging from 2.75 to 7.11%. The genetic analysis including freshwater congeners showed that O. incisa clustered alone occupying a basal position. The Fst pairwise comparisons within O. argentinensis support the existence of three population groups: one conformed by Mar Chiquita Lagoon (MCh) specimens, and the others by Mar del Plata/Mar Chiquita coast and San Blas Bay coastal specimens, respectively. The AMOVA showed significant overall differentiation (Fst = 0.238; p = 0.00001) for the entire data set. The previous/present evidence is discussed, and strongly suggests that incipient speciation is occurring in O. argentinensis argentinean populations, and specimens from MCh would be considered at present as the leading candidate of a marine to freshwater incipient speciation event.

Genetic diversity of the Sichuan snub-nosed monkey ( Rhinopithecus roxellana ) in Shennongjia National Park, China using RAD-seq analyses Abstract The Sichuan snub-nosed monkey (Rhinopithecus roxellana) is an endangered species endemic to China, where the smallest population resides in Shennongjia National Park, Hubei Province. In this study, the genetic diversity of the Sichuan snub-nosed monkeys from two areas, Qianjiaping (QJP) and Dalongtan (DLT) in Shennongjia National Park was evaluated using single nucleotide polymorphisms (SNPs) data derived from restriction site-associated DNA sequencing (RAD-seq). A total of 41,260 SNP loci were found in 29 Sichuan snub-nosed monkey individuals. The genome-wide nucleotide diversity (π) of the Shennongjia population was 0.001842. The genetic differentiation (FST) between the QJP and DLT subpopulations was 0.034. The heterozygosity of individuals from QJP was 0.3475 ± 0.03696 and 0.3148 ± 0.03501 for individuals from DLT. Although the DLT and QJP subpopulations did not show significant genetic differences, genetic differentiation between the two subpopulations was confirmed using Bayesian cluster analysis, neighbor-joining trees and principal component analysis. These results suggest that the Shennongjia population of Sichuan snub-nosed monkey has relatively low genetic diversity at the genomic level. The little genetic differentiation noted between the DLT and QJP subpopulations likely due to natural and anthropogenic barriers which may exacerbate loss of genetic diversity of this endangered subpopulation.

Molecular-genetic diversity of the endangered Dalmatian barbelgudgeon, Aulopyge huegelii from the Buško Blato reservoir Abstract A number of studies investigating different aspects of IUCN endangered species, Aulopyge huegelii Heckel, 1843 (Dalmatian barbelgudgeon) biology have been conducted, but data on molecular genetics are lacking. The goal of this survey was to assess the genetic structure of the A. huegelii population from the Buško Blato reservoir, based on four mitochondrial DNA regions and five microsatellite loci. Excluding cytochrome b, more than one haplotype has been detected in all sequenced mtDNA regions, most of which had not been previously described. A total of seven composite haplotypes were detected. Nucleotide diversity was relatively low for all coding genes but slightly higher for the control region. Microsatellite analysis revealed a relatively high value of major allele frequency, lower values of observed and expected heterozygosity, as well as a moderately reduced number of alleles and genotypes in three of the five observed loci. Although with a clear trend of decline, the level of genetic diversity is still sufficient to ensure the subsistence of the population if the stressors are removed. Otherwise, the loss of heterozygosity will continue, possibly to the point of a complete eradication of the Dalmatian barbelgudgeon from the Buško Blato reservoir.

Identification and expression profiling of selected MADS-box family genes in Dendrobium officinale Abstract Dendrobium officinale, a herb with highly medicinal and ornamental value, is widely distributed in China. MADS-box genes encode transcription factors that regulate various growth and developmental processes in plants, particular in flowering. However, the MADS-box genes in D. officinale are largely unknown. In our study, expression profiling analyses of selected MADS-box genes in D. officinale were performed. In total, 16 DnMADS-box genes with full-length ORF were identified and named according to their phylogenetic relationships with model plants. The transient expression of eight selected MADS-box genes in the epidermal cells of tobacco leaves showed that these DnMADS-box proteins localized to the nucleus. Tissue-specific expression analysis pointed out eight flower-specific expressed MADS-box genes in D. officinale. Furthermore, expression patterns of DnMADS-box genes were investigated during the floral transition process. DnMADS3, DnMADS8 and DnMADS22 were significantly up-regulated in the reproductive phase compared with the vegetative phase, suggesting putative roles of these DnMADS-box genes in flowering. Our data showed that the expressions of MADS-box genes in D. officinale were controlled by diverse exogenous phytohormones. Together, these findings will facilitate further studies of MADS-box genes in Orchids and broaden our understanding of the genetics of flowering.

Compositional properties and codon usage pattern of mitochondrial ATP gene in different classes of Arthropoda Abstract Codon usage bias (CUB) is defined as the usage of synonymous codons unequally for an amino acid in a gene transcript. It is influenced by both mutation pressure and natural selection and is a species-specific property. In our current study, we used bioinformatic methods to investigate the coding sequences of mitochondrial adenosine triphosphate gene (MT-ATP) in different classes of arthropoda to know the codon usage pattern of the gene as no work was described earlier. The analysis of compositional properties suggested that the gene is AT rich. The effective number of codons revealed the CUB of both ATP6 and ATP8 gene was moderate. Heat map showed that the codons ending with AT were negatively associated with GC3 while the codons ending with GC were positively associated with GC3 in all the classes of arthropoda. Correspondence study revealed that the pattern of codon usage of ATP6 and ATP8 genes differed across classes. Neutrality plot suggested the codon usage bias of these two genes in phylum arthropoda was influenced by both mutation pressure and natural selection.

The global male-bias in sex ratio at birth is sustained by the sex ratio genotypes of replacement offspring Abstract Throughout the world, there is a male-bias in the sex ratio at birth (SRB). It is not known whether this phenomenon has a genetic basis, though there is tentative evidence from genealogical and genomic studies that it may have. It has been proposed that the higher rate of male childhood mortality in humans is linked to the male-bias in SRB through parental investment, but this may only apply to facultative not genetic sex ratio adjustment. In previous population genetic models, elevated mortality in one sex (prior to breeding) has been shown not to affect the SRB, but these models did not consider the role of replacement births (i.e. births that only occur because a sibling died prematurely). In a set of population genetic modelling simulations, in which sex ratio is controlled by an autosomal gene expressed in the male line, this study shows that when there is replacement of dead offspring, this leads to a sustained bias in the SRB in the direction of the sex suffering the highest mortality. In the example of higher male mortality, this occurs, because replacement offspring are disproportionately drawn from fathers who were genetically predisposed to have initially had sons (because sons were more likely to die prematurely), and more likely to pass on male-biasing alleles to replacement offspring. To test the empirical basis for replacement births, an analysis of birth data from the Demographic and Health Survey program was conducted, which shows that parents do indeed tend to replace children who die prematurely.

Molecular characterization of class I histone deacetylases and their expression in response to thermal and oxidative stresses in the red flour beetle, Tribolium castaneum Abstract Reversible acetylation of core histones plays an important role in the epigenetic regulation of gene transcription, and is controlled by the action of histone acetyltransferases (HATs) and histone deacetylases (HDACs). While HDACs have been well studied in Drosophila melanogaster, information from insect pests is still limited. In the current study, we cloned and characterized three class I enzymes, TcHDAC1, TcHDAC 3 and TcHDAC 8, in the red flour beetle, Tribolium castaneum. Expression profiling showed that T. castaneum HDAC genes are expressed in all developmental stages and tissues examined. A dramatic increase of mRNA expression level was observed from prepupae to 1-day-old pupae for all three T. castaneum HDAC genes. Both TcHDAC1 and TcHDAC3 exhibited the highest mRNA expression levels in thorax, whereas TcHDAC8 was highly expressed in fat body. Furthermore, T. castaneum HDAC genes were found to respond to heat, cold and oxidative stresses. While the heat-stress treatment decreased the mRNA expression levels of T. castaneum HDAC genes, their transcripts were induced by paraquat treatment. These results suggest a possible role for class I HDAC genes in the epigenetic regulation of T. castaneum development and stress responses.

Genetic mating system, population genetics and effective size of Saffron Finches breeding in southern South America Abstract Thraupidae (Tanagers and allies) show a remarkable array of behaviors, ecologies, morphologies and plumage colors, offering a great opportunity to investigate the evolution of avian mating strategies. We characterize the population genetics and mating system of Sicalis flaveola pelzelni, a socially monogamous Neotropical songbird with biparental care. We found moderate to high levels of neutral genetic variation, similar across three breeding seasons, consistent with large and stable populations, and no temporal genetic structure. Parentage analyses of 114 adults and 198 nestlings (54 nests) revealed 31.8% of extra-pair offspring (EPO) and 51.8% of broods with at least one extra-pair chick. Extra-pair paternity (EPP) rates varied across seasons and were significantly higher in 2014/2015. Neither breeding synchrony nor pair genetic relatedness was significantly associated to EPP rates. Males paired with females in nests with and without EPO were equally heterozygous, and EPO were significantly less heterozygous than within-pair offspring, not supporting the ‘indirect genetic benefits’ hypotheses. Females were more related to their extra-pair mates than to their social mates, not supporting the ‘inbreeding avoidance’ hypothesis. The non-monogamous genetic mating system uncovered here seems not to lower the effective size of the population, which was higher than the sample size of adult breeders. We report and discuss possible cases of quasi-parasitism, as indicated by maternity exclusion patterns. We contribute novel information to expand the knowledge about the largely unexplored genetic mating systems of Thraupidae. Our findings also set the stage for further studies examining if plumage coloration or song traits predict paternity gain or loss in Saffron Finches.

Contemporary and historic patterns of intraspecific diversity in Indian anchovy, Stolephorus indicus , from Indian peninsular waters Abstract We analyzed intraspecific diversity of Indian anchovy, Stolephorus indicus, a commercially and ecologically important species, using mitochondrial DNA markers so as to derive insights into population structuring and historical demography. Analyses were carried out on 128 and 138 individuals collected from 5 locations along the range of distribution using mitochondrial ATPase (843 bp) and COI (663 bp) sequences respectively. Significant connectivity and gene flow was detected among fishes collected from all the geographic locations as indicated by lack of structuring in Bayesian clustering analysis along with insignificant ΦST values. Oceanographic features of the Bay of Bengal, Arabian Sea and Andaman Sea may be favorable for the dispersal of anchovy larvae and subsequent gene flow. Historical demographic analyses indicated a demographic and spatial expansion taken place approximately during 125,000 years before present, the Pleistocene epoch. Indian Ocean witnessed emergence of upwelling events and consequent increase in productivity during the Pleistocene epoch causing a demographic and spatial expansion of anchovies. Management measures for this species should be devised considering it as a single stock along its entire range of distribution.