Chromosomes

Japanese geneticists have for the first time transferred huge quantities of human DNA into mice, a feat that could eventually lead to new ways for producing human proteins effective against a broad variety of diseases. Although researchers have previously been able to introduce human DNA containing a few genes into mice, the Japanese team reports today in the journal Nature Genetics that it was able to insert a whole human chromosome containing more than 1,000 genes.

In a major milestone in the study of human heredity, researchers announced Monday that they have created the first artificial human chromosome, which experts said represents a quantum leap in the ability to probe the complex molecules that make up humankind. The new technology offers scientists a powerful new research tool for investigating fundamental questions about the chemistry responsible for human heredity, experts said.

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.

A team headquartered at UCLA and Cedars-Sinai Research Institute has narrowed the search for a gene causing the mysterious autoimmune disease lupus to a small region of the vast human genome. The finding should lead to better understanding of the causes of the disorder and eventually, to new treatments. Lupus affects as many as 2 million Americans, according to the Lupus Foundation of America.

Defying what some believed to be insurmountable odds, researchers have narrowed the search for a prostate cancer gene to one small corner of the human genetic blueprint, a finding that promises improved diagnosis, new treatments and better survival rates for this most common of male cancers. An estimated 317,000 American men are diagnosed with prostate cancer each year and 40,000 die from it.

Defying what some believed to be insurmountable odds, researchers have narrowed the search for a prostate cancer gene to one small corner of the human genetic blueprint, a finding that promises improved diagnosis, new treatments and better survival rates for this most common of male cancers. An estimated 317,000 American men are diagnosed with prostate cancer each year and 40,000 die from it.

Kaposi's sarcoma, the once-rare form of cancer that has become a hallmark of AIDS, is characterized by specific chromosomal breaks that may be useful in early identification of the disease, according to researchers from the National Cancer Institute. Molecular biologist Nicholas C. Popescu and his colleagues report in the April 3 Journal of the National Cancer Institute that the tumors have specific deletions in the so-called short arm of Chromosome 3, similar to breaks observed in other tumors.

Scientists have linked cardiovascular disease to an age-related breakdown of telomeres, repetitive strings of DNA on the ends of chromosomes. Every time a cell divides, a bit of the telomere is lost. Ultimately, when all the telomere is gone, the cells are unable to divide. Previous research has shown that cancer cells are able to prevent the telomeres from being shortened, and are thus able to continue dividing indefinitely. A team from Geron Corp.

Every man on Earth today is related, linked by a Y chromosome to a common ancestor who lived about 190,000 years ago, a study suggests. This so-called ancestral Adam was among many males who lived before anatomically modern humans evolved, but he's the only one purported in the study to have a genetic legacy that persists today.