"Science and Biotechnology Books Made Simple" |
"Science and Biotechnology Books Made Simple" |
|
Source-
Nature.com
12/10/04 A Genetic Variation Map for Chicken (International Chicken Polymorphism Map Consortium) This is taken directly from Nature.com: A genetic variation map for the chicken genome containing 2.8 million single-nucleotide polymorphisms (SNPs) has been described. This map is based on a comparison of the sequences of three domestic chicken breeds (a broiler, a layer and a Chinese silkie) with that of their wild ancestor, red jungle fowl. Subsequent experiments indicate that at least 90% of the variant sites are true SNPs, and at least 70% are common SNPs that segregate in many domestic breeds. Mean nucleotide diversity is about five SNPs per kilobase for almost every possible comparison between red jungle fowl and domestic lines, between two different domestic lines, and within domestic lines—in contrast to the notion that domestic animals are highly inbred relative to their wild ancestors. In fact, most of the SNPs originated before domestication, and there is little evidence of selective sweeps for adaptive alleles on length scales greater than 100 kilobases. Source-
BB
News 11/8/04 A gene for nicotine addiction is found Scientists California
Institute of Technology are beginning to study a gene for the nicotinic
acetylcholine receptor that is linked to nicotine addiction. When
the “alpha4” subunit of the receptor is mutated in mice, the animals
become unusually sensitive to the effects of nicotine, much like smokers.
These mice showed signs of addiction at lower doses than normal mice. The heritability of nicotine dependence is ~ 50%. According to Dr. Andrew Peacock of the British Thoracic Society, this study points to a specific target for a new drug to treat the problem. Source-
CBC
Health and Science News 9/28/04 Identifying Different Species by DNA Barcodes A new molecular technique called DNA barcoding can identify closely related species of birds and butterflies and aid in finding new ones. The barcode is a short DNA sequence which varies slightly between species. Hebert and his colleagues, of the University of Guelph, studied 260 birds that breed in North America. The samples were taken from specimens at the Royal Ontario Museum in Toronto. The researchers found distinct barcodes in four species, which means the birds may have been improperly lumped in with other species. on part of a gene from the energy-generating mitochondria inside animals cells. The DNA barcode is a gene from mitochondria- a cell organelle involved in energy and respiration. Mitochondrial DNA accumulates mutations at a higher rate than nuclear DNA. Scientists found that DNA sequence of one gene are about 18 times greater difference between species than within a species, the researchers found. The study will help establish a public reference library of DNA bar code for known and newly identified species of plants and animals. Source-
ScienceDaily
9/22/04 New Potential Therapeutics for Spinal Cord Injuries Scientists for the
Christopher Reeve Paralysis Foundation (CRPF) published results of a study
that uses microarray technology to learn about changes in gene expression
after spinal cord injury in the adult rat. The project involving GeneChips
looks at different time points, spanning from three hours after injury to
thirty-five days later. The data analysis also identifies several
promising leads for new clinical treatments. The study is published in the
October issue of Experimental Neurology at http://dx.doi.org/10.1016/j.expneurol.2004.05.042. Microarray technology allows researchers to screen thousands of genes simultaneously to determine which ones are active, or expressed, and which ones are silent. Genes are arrayed on a microchip the size of a fingernail, and experiments are done in a short time. According to Susan P. Howley, CRPF Executive Vice President and Director of Research, microarray technology enables scientists to not only explore gene changes after injury but also to look at genes that are changed after experimental therapy. __________________________________________________
|
