Project description:affy_gnp07_regeneome_cotton - evolution of genotypes and differences - Genes involved in somatic embryogenesis 24 arrays - Cotton; genotype and ecotype comparison,time course The samples are from the following varieties of Gossypium hirsutum (wild type): - Irma from variety NEmb - 1a and B2 are two independent batch of seeds from the variety Coker310. They were selected for their ability to perform embryogenesis. Irma does not embryogenesis after the formation of callus. 1a and b2 have respectively a low and a high capacity for embryogenesis.
Project description:Somatic embryogenesis is an important biotechnological technique for large-scale propagation of elite genotypes. Correlations of stage-specific compounds associated with somatic embryo development can help elucidate the ontogenesis of Carica papaya L. somatic embryos and improve tissue culture protocols. To identify the stage-specific proteins that are present during the differentiation of C. papaya somatic embryos, proteomic analyses of embryos at the globular, heart, torpedo and cotyledonary stages were performed. Comparative proteomic analysis revealed a total of 801 proteins, 392 of which were classified as differentially accumulated proteins in at least one of the developmental stages. The globular stage presented a higher number of unique proteins (16), 7 of which were isoforms of 60S ribosomal proteins, suggesting high translational activity at the beginning of somatic embryogenesis. Proteins related to mitochondrial metabolism accumulated to a high degree at the early developmental stages, after which they decreased with increasing development, contributing to cell homeostasis in early somatic embryos. On the other hand, a progressive increase in the accumulation of vicilin, late embryogenesis abundant proteins and chloroplastic proteins leading to somatic embryo maturation was observed. Additionally, the differential accumulation of acetylornithine deacetylase and S-adenosylmethionine synthase 2 proteins correlated with increased contents of putrescine and spermidine, suggesting that polyamine metabolism is important to somatic embryo development. Taken together, the results showed that somatic embryo development in C. papaya is regulated by the differential accumulation of proteins, with ribosomal and mitochondrial proteins being more abundant during the early somatic embryo stages, while proteins involved in seed maturation are more abundant during the late stages.
Project description:How does environmental change drive phenotypic evolution? We addressed this question using Daphnia genotypes separated by ~1600-years of evolution in a Minnesota lake using methods in resurrection ecology (i.e., reviving dormant eggs from sediments) and found substantial genetic and physiological differentiation. These shifts are highly correlated with anthropogenic environmental change, specifically phosphorus (P)-driven eutrophication. Here, we explore transcriptomic changes that may underlie the observed shifts in P use physiology (see poster by Fricsh et al for a detailed explanation). We compared the transcriptomes of two ancient and two contemporary genotypes in ancient (i.e., low P; LP) and contemporary (i.e., high P; HP) conditions using an 11000-gene microarray. Ancient and contemporary genotypes differed in the number of differentially expressed genes in the HP (mean ± SD; 645 ± 112.95) and LP (1071 ± 211.63) treatments. These results indicate considerable transcriptomic variation between ancient and contemporary genotypes in both dietary treatments, with stressful (LP) conditions invoking differential expression of more genes (t= -2.51; P= 0.04). Moreover, ancient and contemporary genotypes exhibited markedly different transcriptomic responses to dietary treatments. Contemporary genotypes upregulated 84.5 ± 28.99 while ancient genotypes upregulated 413.5 ± 26.16 genes (t= 164.5; P= 0.003). Similarly, ancient (127.5 ± 101.1) and contemporary (316 ± 98.99) genotypes differed significantly in the number of genes downregulated between the HP and LP treatments (t= 125.66; P= 0.005). These results indicate substantial regulatory shifts may underlie the striking physiological differences observed. Further analyses of gene families that were differentially expressed (DE) between ancient and contemporary genotypes revealed several gene families already known to be important in mitigating stoichiometric imbalances driven by P availability. Agglomerative hierarchical cluster analyses of DE loci between ancient and contemporary genotypes indicating age-based clustering will be presented. Together, our theoretical framework based on elemental supply, and unique model system enabled a millennial-scale exploration of the environmental contribution to phenotypic evolution.
Project description:The success of neopteran insects, with 1 million species described, is associated with developmental innovations like the holometaboly and the evolution from short to long germ-band embryogenesis. To unveil the mechanisms underlining these innovations, we compared gene expression during the ontogeny of two extreme neopterans, the cockroach Blattella germanica (polyneopteran, hemimetabolan and short germ-band species), and the fly Drosophila melanogaster (endopterygote, holometabolan and long germ-band species). Results revealed that genes associated with metamorphosis are predominantly expressed in late nymphal stages in B. germanica and in early-mid embryo in D. melanogaster. In B. germanica the maternal to zygotic transition (MZT) concentrates early in embryogenesis, when juvenile hormone factors are significantly expressed. In D. melanogaster, the MZT extends throughout embryogenesis, during which juvenile hormone factors appear unimportant. These differences possibly reflect broad trends in the evolution of development within neopterans, related to the germ-band type and the metamorphosis mode.
Project description:Orphan genes are characteristic genomic features that have no detectable homology to genes in any other species and represent an important attribute of genome evolution as sources of novel genetic functions. Here, we identified 445 genes specific to Populus trichocarpa. Of these, we performed deeper reconstruction of 13 orphan genes to provide evidence of de novo gene evolution. Populus and its sister genera Salix are particularly well suited for the study of orphan gene evolution because of the Salicoid whole-genome duplication event (WGD) which resulted in highly syntenic sister chromosomal segments across the Salicaceae. We leveraged this genomic feature to reconstruct de novo gene evolution from inter-genera, inter-species, and intra-genomic perspectives by comparing the syntenic regions within the P. trichocarpa reference, then P. deltoides, and finally Salix purpurea. Furthermore, we demonstrated that 86.5% of the putative orphan genes had evidence of transcription. Additionally, we also utilized the Populus genome-wide association mapping panel (GWAS), a collection of 1,084 undomesticated P. trichocarpa genotypes to further determine putative regulatory networks of orphan genes using expression quantitative trait loci (eQTL) mapping. Collectively, we provide novel insights into the processes of de novo gene evolution in the context of a long-lived eukaryote.