June 1, 1999 |
Scientists in Hawaii have cloned a trio of identical mice using ordinary cells rather than DNA extracted from the female reproductive system. This time, the cloned critters were male. The clones grew using genetic material extracted from tail cells of adult male mice, but only one grew to adulthood, according to a study in the June issue of the journal Nature Genetics.
December 11, 2004 |
Scientists have identified the cause of Werner syndrome, a rare accelerated aging disease whose sufferers prematurely develop gray hair, wrinkled skin, cataracts, cancer and heart disease, dying in their 40s. Researchers at the Salk Institute for Biological Studies in La Jolla reported in the journal Science that patients with Werner syndrome couldn't properly replicate the ends of their chromosomes due to a defective gene, WRN.
December 19, 2000 |
Scientists at Texas A&M University in College Station unveiled a disease-resistant black Angus bull, saying it could lead to safer beef and more efficient ranching worldwide. The month-old calf, called Bull 86 Squared, was cloned from genetic material frozen 15 years ago from Bull 86.
March 30, 2002 |
French researchers reported today that they had succeeded in cloning rabbits using genetic material from adult cells. The animal joins sheep, cattle, goats, mice, pigs and cats in the select but rapidly growing fraternity of cloned organisms. The four cloned female rabbits were born last year at the National Institute for Agronomical Research outside Paris.
July 2, 2001 |
The conventional idea that most living organisms require two parents has been challenged by Dutch and Czech researchers, who have found a species that has only mothers. They report in the June 29 Science that a species of tropical mite (Brevipalpus phoenicius) consists entirely of females with only one set of genetic material. Most animals have two sets, one from each parent. The male of the mite species is all but nonexistent.
CALIFORNIA | LOCAL
February 20, 1997 |
Small defects in the male chromosome may be responsible for some cases of infertility, University of Minnesota doctors report in the New England Journal of Medicine. Dr. Jon Pryor and his team found that 7% of the 200 infertile men they studied were missing tiny pieces of their Y chromosomes, genetic material found only in males. However, further study revealed that the deleted pieces did not always cause infertility.
October 11, 2008 |
Scientists have confirmed the second case of a "virgin birth" in a shark. In a study reported Friday in the Journal of Fish Biology, scientists said DNA testing showed that a pup carried by an Atlantic blacktip shark at the Virginia Aquarium & Marine Science Center contained no genetic material from a male. In 2007, the female shark died of complications from an unknown pregnancy. Her pup was found during a necropsy. No male blacktips were present in her eight years there.
December 24, 2001
British scientists have mapped chromosome 20, the third and longest chromosome to be sequenced in the Human Genome Project. Chromosome 20 is best known for harboring genes that contribute to forms of the brain-wasting Creutzfeldt-Jakob disease and severe-combined immunodeficiency, an illness in which the immune system is crippled. Chromosome 20 contains 727 genes and accounts for about 2% of the total human genetic material, the team reported in the Dec. 20 issue of Nature.
CALIFORNIA | LOCAL
December 2, 1991 |
A quick and easy way to remove so-called "marker genes" that are used during the genetic engineering of plants has been developed by researchers at the U.S. Department of Agriculture's research center at Albany. The development is likely to lead to quicker approval of genetically engineered foodstuffs. The markers are inserted into a plant's genes along with a desired gene so that researchers will have an easy way to tell if the insertion was successful.