BACE1 gene promoter single-nucleotide polymorphisms in Alzheimer's disease.

Alzheimer's disease (AD) is the most neurodegenerative disorder leading to dementia. Neuritic plaque formation in brains is a hallmark of AD pathogenesis. Amyloid beta protein (Abeta) is the central component of neuritic plaques.

Sexual selection and the geography of Plasmodium infection in Savannah sparrows (Passerculus sandwichensis).

According to Hamilton and Zuk's hypothesis of parasite-mediated sexual selection, host-parasite coevolution maintains variation in male genetic quality and allows for strong intersexual selection in species with high rates of infection. In birds, most interspecific tests of this hypothesis relate the prevalence of blood parasites to some measure of the intensity of sexual selection. Such tests often rely on limited sampling of single populations to estimate species-wide infection rates, and many tests are thus vulnerable to intraspecific (geographic) variation in the evolutionary ecology of disease.