Technology

Association testing by DNA pooling: an effective initial screen. Bansal, A. et al. Proc. Natl Acad. Sci. USA 99, 16871–16874 (2002)

High-throughput screening for evidence of association by using mass spectrometry genotyping on DNA pools. Mohlke, K. L. et al. Proc. Natl Acad. Sci. USA 99, 16928–16933 (2002)

Despite the increasing number of molecular markers that have become available, whole-genome scans for association between such markers and a disease are hindered by the number of genotyping reactions that need to be carried out and by the limiting amount of available DNA. These two studies provide evidence that DNA pooling — in which the case and control samples are genotyped as two large groups — is a valid alternative to sample-by-sample genotyping. Mohlke et al. have shown empirically that pooled SNP genotyping is comparable to individual genotyping in detecting differences in allelic frequency between cases and controls, whereas Bansal et al. have found a significant association between SNPs in the cholesterol ester transferase protein (CETP) gene and levels of serum HDL cholesterol.

Population genetics

Genetics affinities of the Andaman Islanders, a vanishing human population. Thangaraj, K. et al. Curr. Biol. 26 November 2002 (10.1016/S0960982202013362)

Disputes over the origin of the now nearly extinct inhabitants of the Andaman Islands have been laid to rest. Although they resemble African pygmies, the islanders have been considered to be more likely descendants of Southeast Asian settlers. The authors' analysis of mitochondrial DNA, RFLP and microsatellite markers from various local tribes showed that they are the descendants of the early Palaeolitic Southeast Asian colonizers, distinct from their neighbours on a separate, but near-by, group of islands.

Animal models

Zebrafish as a model organism for the identification and characterization of drugs and genes affecting p53 signaling. Langheinrich, U. et al. Curr. Biol. 12, 2023–2028 (2002)

The activity of the p53 gene is crucial in determining tumour progression as it mediates apoptosis and cell-cycle control. By using morpholinos to knockdown zebrafish gene activity, Langheinrich et al. show that the key components of p53 signalling are conserved between mammals and zebrafish. As cancer treatment drugs have a similar effect in both zebrafish and mammals, zebrafish could be a good system in which to carry out high-throughput screens for genes and compounds affecting p53 signalling. Results could then inform the development of new cancer therapies.