W. Rohde

Remains of barley (Hordeum vulgare) grains found at archaeological sites in the Fertile Crescent indicate that about 10,000 years ago the crop was domesticated there from its wild relative Hordeum spontaneum. The domestication history of barley is revisited based on the assumptions that DNA markers effectively measure genetic distances and that wild populations are genetically different and they have not undergone significant change since domestication. The monophyletic nature of barley domestication is demonstrated based on allelic frequencies at 400 AFLP polymorphic loci studied in 317 wild and 57 cultivated lines. The wild populations from Israel-Jordan are molecularly more similar than are any others to the cultivated gene pool. The results provided support for the hypothesis that the Israel-Jordan area is the region in which barley was brought into culture. Moreover, the diagnostic allele I of the homeobox gene BKn-3, rarely but almost exclusively found in Israel H. spontaneum, is pervasive in western landraces and modern cultivated varieties. In landraces from the Himalayas and India, the BKn-3 allele IIIa prevails, indicating that an allelic substitution has taken place during the migration of barley from the Near East to South Asia. Thus, the Himalayas can be considered a region of domesticated barley diversification.

To investigate possible permanent consequences of an early postnatal overfeeding, the following experimental model was used: Male Wistar rats were divided into three groups after birth: (1) Small litters with 3-4 newborns (overnutrition), (2) normal litters with 12 animals (normonutrition), and (3) large litters with 20-24 newborn rats (undernutrition). After weaning all animals had free access to tap water and standard pellet diet. The serum insulin level of animals from small litters on day 15 of life was highly significantly increased as compared to the other groups. These overfed hyperinsulinaemic rats showed a higher body weight gain during the suckling period trough juvenile life until adulthood, associated with enhanced mean food intake and resulting in an increased relative body weight (per body length) as a sign of obesity. The obesity was found to be correlated with basal hyperinsulinaemia and increased systolic blood pressure in the small-litter-adults. Moreover, the early postnatally overnourished animals developed an increased type I-like diabetes susceptibility to a "subdiabetogenic" dose of streptozotocin in adulthood. These results suggest once more that hyperinsulinism during brain differentiation, in the present experiment induced by early postnatal overnutrition, may represent a predisposing factor for the development of obesity, of increased diabetes susceptibility and also of increased cardiovascular risk in later life.