Serial Endosymbiosis Theory: From biology to astronomy and back to the origin of life.

Serial Endosymbiosis Theory, or SET, was conceived and developed by Lynn Margulis, to explain the greatest discontinuity in the history of life, the origin of eukaryotic cells. Some predictions of SET, namely the origin of mitochondria and chloroplasts, withstood the test of the most recent evidence from a variety of disciplines including phylogenetics, biochemistry, and cell biology. Even though some other predictions fared less well, SET remains a seminal theory in biology. In this paper, I focus on two aspects of SET. First, using the concept of "universal symbiogenesis", developed by Freeman Dyson to search for commonalities in astronomy and biology, I propose that SET can be extended beyond eukaryogenesis. The extension refers to the possibility that even prokaryotic organisms, themselves subject to the process of symbiogenesis in SET, could have emerged symbiotically. Second, I contrast a recent "viral eukaryogenesis" hypothesis, according to which the nucleus evolved from a complex DNA virus, with a view closer to SET, according to which the nucleus evolved through the interplay of the archaeal host, the eubacterial symbiont, and a non-LTR transposon, or telomerase. Viruses joined in later, through the process of viral endogenization, to shape eukaryotic chromosomes in the process of karyotype evolution. These two proposals based on SET are a testament to its longevity as a scientific theory.

A half century of infrared astronomy - A personal recollection of the footprints in Japan.

Since the new era of infrared astronomy was opened by the Two Micron Sky Survey by Neugebauer et al. in the early 1960s, about a half century has passed. During this time, observations have expanded rapidly and widely, to almost every field of astronomy, to reveal new perspectives on the universe. As a result, infrared astronomy has become one of the major branches of astronomy, along with optical, radio, X-ray as well as high-energy particle astronomy. In Japan, we started our infrared astronomical activities at a rather early time, under relatively poor technical and environmental conditions, and using somewhat unconventional methods to overcome these difficulties. Here, a brief survey is presented of developments concerning infrared astronomy during the past half century, while mainly recollecting our footprints in the stream of world activities.

Big Data: Astronomical or Genomical?

Genomics is a Big Data science and is going to get much bigger, very soon, but it is not known whether the needs of genomics will exceed other Big Data domains. Projecting to the year 2025, we compared genomics with three other major generators of Big Data: astronomy, YouTube, and Twitter. Our estimates show that genomics is a "four-headed beast"--it is either on par with or the most demanding of the domains analyzed here in terms of data acquisition, storage, distribution, and analysis. We discuss aspects of new technologies that will need to be developed to rise up and meet the computational challenges that genomics poses for the near future. Now is the time for concerted, community-wide planning for the "genomical" challenges of the next decade.