Detecting immigration by using multilocus genotypes

Immigration is an important force shaping the social structure, evolution, and genetics of populations. A statistical method is presented that uses multilocus genotypes to identify individuals who are immigrants, or have recent immigrant ancestry. The method is appropriate for use with allozymes, microsatellites, or restriction fragment length polymorphisms (RFLPs) and assumes linkage equilibrium among loci. Potential applications include studies of dispersal among natural populations of animals and plants, human evolutionary studies, and typing zoo animals of unknown origin (for use in captive breeding programs). The method is illustrated by analyzing RFLP genotypes in samples of humans from Australian, Japanese, New Guinean, and Senegalese populations. The test has power to detect immigrant ancestors, for these data, up to two generations in the past even though the overall differentiation of allele frequencies among populations is low.

Batrachotoxin alkaloids from passerine birds: A second toxic bird genus (Ifrita kowaldi) from New Guinea

Batrachotoxins, including many congeners not previously described, were detected, and relative amounts were measured by using HPLC-mass spectrometry, in five species of New Guinean birds of the genus Pitohui as well as a species of a second toxic bird genus, Ifrita kowaldi. The alkaloids, identified in feathers and skin, were batrachotoxinin-A cis-crotonate (1), an allylically rearranged 16-acetate (2), which can form from 1 by sigmatropic rearrangement under basic conditions, batrachotoxinin-A and an isomer (3 and 3a, respectively), batrachotoxin (4), batrachotoxinin-A 3′-hydroxypentanoate (5), homobatrachotoxin (6), and mono- and dihydroxylated derivatives of homobatrachotoxin. The highest levels of batrachotoxins were generally present in the contour feathers of belly, breast, or legs in Pitohui dichrous, Pitohui kirhocephalus, and Ifrita kowaldi. Lesser amounts are found in head, back, tail, and wing feathers. Batrachotoxin (4) and homobatrachotoxin (6) were found only in feathers and not in skin. The levels of batrachotoxins varied widely for different populations of Pitohui and Ifrita, a result compatible with the hypothesis that these birds are sequestering toxins from a dietary source.