The dominant allele is expressed and the recessive allele is masked. This is an example of complete dominance. In heterozygous relationships where neither allele is dominant but both are completely expressed, the alleles are considered to be co-dominant. Co-dominance is exemplified in AB blood type inheritance.
swale (plural swales) 1  A low tract of moist or marshy land. 2  A long narrow and shallow trough between ridges on a beach, running parallel to the coastline. 3  A shallow troughlike depression that's created to carry water during rainstorms or snow melts; a drainage ditch.
The swale concept has also been popularized as a rainwater harvesting and soil conservation strategy by Bill Mollison, Geoff Lawton and other advocates of permaculture. In this context it usually refers to a water-harvesting ditch on contour.his type of swale is created by digging a ditch on contour and piling the dirt on the downhill side of the ditch to create a berm. In arid climates, vegetation (existing or planted) along the swale can benefit from the concentration of runoff.