Genes & cells.Making the human The human version of a stretch of DNA DNA: see nucleic acid. DNA or deoxyribonucleic acid One of two types of nucleic acid (the other is RNA); a complex organic compound found in all living cells and many viruses. It is the chemical substance of genes. responsible for turning genes on and off spurs development in mouse limbs, but the same stretch of DNA from chimps does not. The difference points to a genetic change that may be crucial in setting humans apart from other primates (SN: 9/27/08, p. 13). Do-it-yourself DNA Making a complete microbial microbial pertaining to or emanating from a microbe. microbial digestion the breakdown of organic material, especially feedstuffs, by microbial organisms. genome from scratch by assembling the individual letters of its genetic code paves the way for making synthetic microbes (SN: 1/26/08, p. 52). Reading genomes Researchers publish the genomes for a choanoflagellate (SN: 2/16/08, p. 99), platypus platypus (plăt`əpəs), semiaquatic egg-laying mammal, Ornithorhynchus anatinus, of Tasmania and E Australia. Also called duckbill, or duckbilled platypus, it belongs to the order Monotremata (see monotreme), the most primitive group (SN Online: 5/8/08) and a transgenic papaya papaya (pəpī`ə), soft-stemmed tree (Carica papaya) of tropical America resembling a palm with a crown of palmately lobed leaves. (SN: 5/10/08, p. 9). Reviving extinct DNA Scientists insert a bit of DNA from the extinct Tasmanian tiger into a mouse embryo (below). The DNA turns on a gene in the mouse's cartilage-producing cells (SN: 6/7/08, p. 9). [ILLUSTRATION OMITTED] Energizer mouse Two drugs, one that stimulates a gene and another that targets a protein, can boost the running endurance of mice by about 75 percent and 45 percent (SN: 8/30/08, p. 14). Ch-ch-ch-changes Chemical tags that affect gene activity change over a person's lifetime, and the changes follow similar patterns among family members (SN: 7/19/08, p. 9). Common age Research on aging finds yeast and roundworms share 25 longevity-related genes; humans have 15 of these genes (SN: 3/15/08, p. 164). Community of one Scientists discover a single bacterial species, Candidatus Desulforudis audaxviator (shown above), living deep in a gold mine in South Africa. Its genome contains everything it needs to live independently (SN: 11/8/08, p. 20). [ILLUSTRATION OMITTED] Stem cell stem cell In living organisms, an undifferentiated cell that can produce other cells that eventually make up specialized tissues and organs. There are two major types of stem cells, embryonic and adult. snag In a possible setback for scientists developing stem cell therapies stem cell therapy Cell therapy Molecular medicine A technology in which a person's own cells–eg, neuronal stem cells are triggered to revert to their primitive embryonic form, then redifferentiate into mature cells of various organs for Parkinson's disease Parkinson's disease or Parkinsonism, degenerative brain disorder first described by the English surgeon James Parkinson in 1817. When there is no known cause, the disease usually appears after age 40 and is referred to as Parkinson's disease. , researchers find that some nerve cells transplanted into the brains of Parkinson's patients show signs of getting the disease as many as 16 years after the transplant (SN: 4/12/08, p. 229). --Elizabeth Quill, News Editor |
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