In a Brief Communication in the July 12 Nature, Pardini et al. report the use of genetic analysis to track the movements of great white sharks, Carcharodon carcharias (Nature 2001, 412:139-140). Analysis of DNA sequences from the maternally inherited mitochondrial genome provided evidence for long-term isolation of female sharks in three distinct populations (off the coasts of South Africa, Australia and New Zealand). In contrast, they found no sequence differentiation for microsatellite loci in

The Cape province of South Africa is considered a continental ' hotspot' with a rich diversity of species of flora. In the July 12 Nature, Richardson et al., from the Royal Botanic Gardens in Richmond, UK, report the results of a molecular phylogenetic analysis that dates the era of speciation to about 7-8 million years ago (Nature 2001, 412:181-182). They sequenced nuclear ribosomal and plastid DNA from island species of the buckthorn Phylica, as well as continental species from the Cape, and

gene causes susceptibility to mycobacteria without affecting viral immunity.

Pin1, a member of a new family of phosphorylation-specific peptidyl-prolyl isomerases (PPIases), regulates mitosis and neuronal cell death in Alzheimer's disease. In the July 2 EMBO Journal, Wulf et al. propose a mechanism by which Pin1 may contribute to cell proliferation in breast cancer cells (EMBO Journal 2001, 20:3459-3472). They found that Pin1 was overexpressed in breast cancer tissue and correlated with the tumour grade and with the level of cyclin D1 expression. Wulf et al. show that Pi

The apoptotic suicide programme involves fragmentation of nucleosomal DNA. In the July 5 Nature, two groups report identification of a mitochondrial nuclease that induces DNA degradation associated with apoptosis in both worms and mammals. Parrish et al. performed a genetic screen in Caenorhabditis elegans to search for suppressors of an activated cell-death protease (CED-3) mutant (Nature 2001, 412:90-94). After screening 3,000 mutagenized haploid genomes, they identified an apoptosis-related g

In the July 6 Science, Humpherys et al. describe extensive analysis of the expression of imprinted genes in mice derived from cloning by nuclear transfer (NT) (Science 2001, 293:95-97). They examined mRNA levels for several imprinted genes including H19 and Igf2, Peg1/Mest, Mest/Grb10, Peg3 and Snrpn. They found that the expression of imprinted genes varied widely between the placentas of cloned embryos and in the organs of newborn cloned mice. H19 expression was often silenced and Igf2 expressi

The surprising plasticity and trans-differentiation of transplanted stem-cells suggest that there may be a set of universal stem-cell genes that govern the undifferentiated proliferative state. In the July 3 Proceedings of the National Academy of Sciences, Terskikh et al. report attempts to define a common stem-cell gene profile by comparing hematopoietic and neural stem-cells (Proc Natl Acad Sci USA 2001, 98:7934-7939). They isolated hematopoietic stem cells (HSC) from mouse bone marrow and cre

The hippocampus plays a role in the brain's ability to learn and remember. In the Early Edition of the Proceedings of the National Academy of Sciences, Mody et al. report the use of a microarray strategy to define genes involved in the development and function of the mouse hippocampus. They used Affymetrix oligonucleotide arrays to screen for the expression profiles of 11,000 genes in embryonic (E16) or postnatal (P1, P7, P16 and P30) mouse hippocampus tissue. They found that 1,926 genes showed

The gene-trap strategy can exploit insertional mutagenesis to allow phenotypic screening. In the July issue of Nature Genetics, Mitchell et al. demonstrate the power of gene-trap mutagenesis for genome-wide analysis of the genes involved in mouse development (Nature Genetics 2001, 298:241-24). Their modified 'secretory-trap' vector selects genes that have secretory signal sequences or transmembrane domains. Screening over 500 insertions in mouse embryonic stem (ES) cells identified 187 individua

Translocations in acute megakaryoblastic leukemia result in the fusion of two novel genes.

Mutations in matrix metalloproteases have been detected in inherited osteolytic and arthritic disorder.

The Id1 protein inhibits cell senescence by repressing cell-cycle genes.