John MC Ma and Sara Hanson will present their research on June 7th 2012

John MC Ma’s Research summary

Fine mapping Metabolic Syndrome QTL by genome resequencing
The Lyon rat strains consists of Lyon Hypertensive (LH) strain, an established model for human metabolic syndrome (MetS); Lyon Low-Pressure (LL), which is obese but is protected towards most MetS syndromes; and Lyon Normotensive (LN), a phenotypically normal control. Through high-throughput genome resequencing on the Lyon strains, we have been able to further fine map the QTL regions for many of MetS’ symptoms on chromosome 17 (RNO17) to 8 tighly clustered putative haplotype regions with a total length of 7.5mb and overlaps with 26 genes. Phenotype-based analyses have further subgrouped these gene as candidate genes for obesity and those for many symptoms of MetS.

Sara Hanson’s Research summary

Genome and Transcriptome Analysis of Sexual and Asexual Reproduction in Monogonont Rotifers
How sexual reproduction has persisted in nature is an important and unsolved evolutionary question. As cyclical parthenogens, monogonont rotifers have overcome constraints on the loss of sexual reproduction in order to frequently transition between sexual and asexual generations. This makes monogononts apowerful system with which to address the maintenance of sex in animals. However, the molecular nature of meiosis and parthenogenesis in these species is poorly understood. To expand our knowledge of the molecular mechanisms of monogonont reproduction, we sequenced draft genomes of two distantly related species, Brachionus calyciflorusand B. manjavacas. We searched the genome ofeach species for genes involved in meiotic processes, and identified over eighty meiotic gene homologs. Several of these genes have undergone duplication events specific to the monogonont lineage, including genes with known roles in regulation of cell cycle transitions during meiosis. In addition, global gene expression patterns were determined through generation of mRNA-seq libraries from obligate parthenogenetic (OP) and cyclical parthenogenetic (CP) strains of B. calyciflorus. Quantitative comparison of expression between these libraries revealed differentially expressed genes specific to sexual and asexual reproduction in this species, including genes related to dormancy/resting egg formation and hormone signaling pathways that are thought to be involved in the induction of sexual reproduction in monogononts. Furthermore, several genes contained in the genomic inventory of meiotic genes were differentially expressed. The presence of cell cycle regulatory gene duplications and their differential expression between OP and CP strains is consistent with data from cyclical parthenogenetic arthropod species, suggesting mechanisms for convergent evolution of this reproductive mode. Furthermore, establishing molecular markers for sex and asex in monogononts will allow for more informed analyses of our ongoing gene expression studies in ancient asexual bdelloid rotifers, who possess a number of genes specific to meiosis.

Posted on May 31, 2012, in Student Seminar. Bookmark the permalink. Leave a comment.

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