Interthallic Sexual Reactions Among Achlya Isolates from Natural Populations

ABSTRACT

Achlya isolates from three natural populations were examined to determine the potential for sexual interactions among the inhabitants of a specific pond. Conjugation tests of these isolates with males and females of A. ambisexualis, A. bisexualis, and A. heterosexualis revealed extensive cross conjugation-compatibility between individual isolates and the test strains. A gynandromictic index was used to classify the isolates according to conjugation compatibility and potential. Homothallic isolates showed a bias towards maleness. The populations of each pond appeared to be distinctive. Of the three ponds, a temporary one yielded only homothallic strains. The two permanent ponds differed in diversity of mating types, one yielding five, the other two types. Isolates from each pond were subjected to conjugation tests in all possible pair-wise combinations. The potential for sexual reproduction between gynandromictic Achlya isolates found together in nature has been established.

Key Words:

• Achlya
• conjugation
• gynandromictic
• populations