Period Of Geographical Isolation Research Articles

Hemoglobin and transferrin electrophoresis and relationships of island populations of Anolis lizards.

Electrophoretic differences in hemoglobins and transferrins serve to differentiate Anolis of the same species populating the Lesser Antilles. When based on protein analyses, identifications of individuals may be less equivocal than identification based on descriptions of skin color and markings. Protein differences among island populations appear to be associated with long periods of geographic isolation. Such evidence often confirms estimates of relationship derived from more traditional criteria and in some cases provides a basis for formulating new taxonomic conclusions.

Sexual isolation in some North American Anopheles mosquitoes.

Summary and ConclusionsCross mating experiments were designed to show whether sexual isolation exists between Anopheles quadrimaculatus, A. freeborni and A. aztecus.It was found that a definite barrier to cross mating exists between males of A. quadrimaculatus and females of A. freeborni and A. aztecus, between males of A. aztecus and females of A. quadrimaculatus and A. freeborni, and between A. freeborni males and A. quadrimaculatus females. However, A. aztecus females were fertilized as readily by A. freeborni males as were A. freeborni females.These results support conclusions drawn from other studies that A. aztecus and A. freeborni are much more closely related to one another than they are to A. quadrimaculatus. Sexual isolation could be a secondary result of long geographic separation. There is only a partial barrier between the A. freeborni and A. aztecus and although this might contribute towards a segregation of the two populations, the readiness with which A. aztecus females will mate with males of A. freeborni, even after a long period of geographic isolation, would lead one to suspect that in this case the primary dividing mechanism was not sexual isolation. This isolation would aid, however, in keeping the present-day populations distinct should their ranges overlap.