Reduction of the Edited Domain of the Mitochondrial A6 Gene for ATPase Subunit 6 in Trypanosomatidae

The sequence of mitochondrial A6 (MURF4) was compared for several trypanosomatids in order to assess the reduction of the edited domain (ED). The association between the ED reduction and the phylogenetic position of a species proved to be less tight than believed earlier. Compared with digenetic species, monogenetic ones more often displayed ED reduction and had smaller ED.     

Variation in genetic traits of the Baltic clam Macoma balthica from a tidal gradient in the subarctic

In a subarctic tidal gradient, strong heterogeneity in genetic traits of the Baltic clam Macoma balthica was found. The heterogeneity was stronger within the intertidal gradient, over a distance of only about 60 m, than along a horizontal gradient over a distance of 1200 km in clams from the west European coast. For the locus Idh1 and the average heterozygosity, a tidal cline was found. The frequency of allele Idh1-B decreased with tidal level, whereas the frequency of allele Idh1-C, as well as the average heterozygosity, increased. The possibility is discussed that the strong genetic heterogeneity and tidal clines are caused by differential selection related to the (subarctic) temperatures to which the higher tidal zones are more exposed. Received: 7 July 1997 / Accepted: 14 November 1997