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Archive - Mar 25, 2014

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Sea Anemone Shows Characteristics of Both Plant and Animal in Gene Regulation

A team led by evolutionary and developmental biologist Dr. Ulrich Technau at the University of Vienna has discovered that sea anemones display a genomic landscape with a complexity of regulatory elements similar to that of fruit flies or other animal model systems. This suggests, that this principle of gene regulation is already 600 million years old and dates back to the common ancestor of human, fly, and sea anemone. On the other hand, sea anemones are more similar to plants rather thn to vertebrates or insects in their regulation of gene expression by short regulatory RNAs called microRNAs. These surprising evolutionary findings were published on March 18, 2014 in two open-access articles in Genome Research. Our appearance, the shape we have and how our body works is, in addition to environmental influences, largely the result of the action of our genes. However, genes are rarely single players, they rather act in concert and regulate each other's activity and expression in gene regulatory networks. In the last decades, the sequencing of the human and many animal genomes has shown that anatomically simple organisms such as sea anemones have a surprisingly complex gene repertoire similar to that of higher model organisms. This implies, that the difference in morphological complexity cannot be easily explained by the presence or absence of individual genes. Some researchers hypothesized that the individual genes do not code for more complex body plans, but that this is determined by how the genes are wired and linked between each other. Accordingly, researchers expected that these gene networks are less complex in simple organisms than in human or "higher" animals. A measurement of the complexity of gene regulation could be the distribution and density of regulatory sequences in the genome.

Scientists Identify Gene That May Influence the Timing of Puberty

Scientists have identified a gene that may influence the timing of puberty, according to research presented on Mrch 25, 2014 at the Society for Endocrinology annual BES conference in Liverpool, United Kingdom. Until now, very little has been known about the genetic control of puberty. More than 4% of adolescents suffer from early or late-onset puberty, which is associated with health problems including obesity, type-2 diabetes, cardiovascular disease, and cancer. The findings of the study are expected to make diagnosis easier and more efficient, reducing the risk of disease. Researchers from Queen Mary University of London scanned the genomes of seven families experiencing delayed puberty. The genetic profiles were analyzed to identify specific genes that were different in these families, compared to individuals who started puberty normally. The researchers identified 15 candidate genes that were then examined in a further 288 individuals with late-onset puberty. One gene was found to have common variants in nine families. The gene appears to contribute to the early development of gonadotropin-releasing hormone (GnRH) neurons in the brain. At puberty, a surge of GnRH is released, signaling to the pituitary gland to release further hormones that act on the ovaries and testes, triggering reproductive function (sexual maturation). If development of the GnRH neurons is delayed, the surge of GnRH that initiates these signals is also delayed. Dr. Sasha Howard, who led the study, said, “Studies estimate that 60-80% of variation in the timing of puberty is genetically determined, yet this is one of the first genes with major impact to be identified.