C4 photosynthesis evolved independently numerous times, probably in response to declining atmospheric CO2 concentrations, but also to high temperatures and aridity, which enhance water losses through transpiration. Here, the environmental factors controlling stomatal behaviour of leaf-level carbon and water exchange were examined across the evolutionary continuum from C3 to C4 photosynthesis at...

Serum C4 concentrations were measured in 102 healthy subjects and 90 subjects with type I diabetes mellitus. A wide range was observed in the group as a whole (0.08-0.67 g/l; mean = 0.26 g/l; SEM = 0.01 g/l). After C4 allotyping it was possible to subgroup 134 of these subjects according to the number of C4 null alleles present. C4 concentrations in the group with two null alleles were lower th...

The complement component C4 is well known for its complex genetics in human and mouse where it is part of a tandemly duplicated module. For the rat, no such information had been available until recently. A C4 gene duplication could be identified also in the rat, but the duplicated module maps approximately 200 kb centromerically from the canonical C4-1 gene. In this study, we present the genomi...

C4 photosynthesis is a physiological innovation involving several anatomical and biochemical components that emerged recurrently in flowering plants. This complex trait evolved via a series of physiological intermediates, broadly termed 'C3-C4', which have been widely studied to understand C4 origins. While this research program has focused on biochemistry, physiology, and anatomy, the ecology ...