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This Week in Science: Sep 28, 2007

The US will no longer be part of an international test of advanced mathematics and physics, reports Science. The National Center for Education Statistics says that it cannot afford the test's cost, but critics say that the Bush administration is pulling out because a bad performance on international tests would reflect badly on the No Child Left Behind Act.

Researchers led by Hilary Morrison describe the genome of the protist Giardia lamblia, a human intestinal parasite. This early eukaryote contains two nuclei, but lack mitochondria and peroxisomes, and much of its cellular processes are simplified. Giardia has two origin recognition complex proteins and its RNA processing machinery is less complex than other eukaryotes'. Even with Giardia's genome, there are still questions about this protist's past. "The evolutionary history of Giardia is not so clearly written in the genome, reigniting a smoldering debate about the origin of Giardia and its relationship to other eukaryotes," writes the University of British Columbia's Patrick Keeling in a related Perspectives article.

Using sequence-by-synthesis technology on 10 ancient mammoth hairs, scientists led by M. Thomas P. Gilbert report that they sequenced the Siberian mammoth's mitochondrial genome with 48-fold coverage. They also compared the SBS technique to using bone samples. The SBS and coat hair method yielded fewer sequencing errors than using frozen bone samples or bone samples kept at room temperature, and it yielded mtDNA sequence 5.75 to 26 times higher.


The Scan

Tens of Millions Saved

The Associated Press writes that vaccines against COVID-19 saved an estimated 20 million lives in their first year.

Supersized Bacterium

NPR reports that researchers have found and characterized a bacterium that is visible to the naked eye.

Also Subvariants

Moderna says its bivalent SARS-CoV-2 vaccine leads to a strong immune response against Omicron subvariants, the Wall Street Journal reports.

Science Papers Present Gene-Edited Mouse Models of Liver Cancer, Hürthle Cell Carcinoma Analysis

In Science this week: a collection of mouse models of primary liver cancer, and more.