Enzyme function and polymorphism: a test in two Anolis lizard species

Area of Science:

• * Evolutionary biology
• * Molecular ecology
• * Herpetology

Background:

• * Enzyme variability in species is influenced by factors like enzyme function and thermal regulation.
• * Anolis gundlachi lizards are ectothermic and experience a coarse-grained thermal environment.
• * Anolis roquet lizards behaviorally regulate body temperature, experiencing a fine-grained thermal environment.

Purpose of the Study:

• * To investigate the relationship between enzyme variability and enzyme function in two Anolis lizard species.
• * To test if thermal environment differences correlate with enzyme heterozygosity levels.
• * To determine which enzyme classes contribute to interspecific differences in heterozygosity.

Main Methods:

• * Electrophoretic surveys were conducted on enzyme variability in Anolis roquet and Anolis gundlachi.
• * Enzyme loci were categorized by substrate specificity (single- vs. multiple-substrate) and regulatory role (regulatory vs. nonregulatory).
• * Heterozygosity levels were compared between the two species and across enzyme classes.

Main Results:

• * Anolis gundlachi exhibited significantly higher overall enzyme heterozygosity compared to Anolis roquet.
• * The elevated heterozygosity in A. gundlachi was primarily attributed to loci coding for multiple-substrate enzymes.
• * The distinction between regulatory and nonregulatory enzymes did not explain the observed variability in heterozygosity.

Conclusions:

• * Enzyme heterozygosity levels are species-specific and influenced by ecological factors, such as thermal niche.
• * Multiple-substrate enzymes may be more sensitive to environmental variation, leading to higher heterozygosity in species with less precise thermal regulation.
• * Enzyme function, specifically substrate complexity, is a key factor in understanding patterns of genetic variability in lizards.