Heritable variation for sex ratio under environmental sex determination in the common snapping turtle (Chelydra serpentina)

Article Abstract:

The common snapping turtle exhibits temperature-dependent sex determination (TSD), wherein the sex of offspring is determined after conception by temperatures exprerienced during egg incubation.To determine if there is significant interaction between genotype and environment (G x E) in determing the primary sex ratio of a species with TSD, eggs of different families of snapping turtles were subjected to three different incubation temperatures. The results showed significant effects of family and incubation temperatures on sex ratio, but no significant interactionwas detected. Therefore, G x E interactions are not the primary mechanisms maintaining sex ratio variations.

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Sources of variation in leaf shape among two populations of Achillea lanulosa

Article Abstract:

Variations in leaf morphology of Achillea lanulosa found in high and intermediate altitudes were measured. Plants from both regions were cloned, replicated and grown in controlled environment having warm and cool conditions. Both environments were exposed to bright lights. Leaves from plants living in high altitudes were shorter and more packed with segments while those at lower regions were more longer and open. These plants retained their differences in size and shape even when grown in the same environment. Leaves produced by both plants adapted their shape and size according to the temperatures of the regions when subjected to varying temperatures.

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The effect of adaptive mutagenesis on genetic variation at a linked, neutral locus

Article Abstract:

Adaptive mutagenesis influences the genetic structure of a population in a selective sweep, and its presence increases the quantity of A1 alleles in B1 and B2 backgrounds. Less adaptive change at a selected locus is due to adaptive mutagenesis than is due to natural selection, but the adaptive mutagenesis has a strong effect on the linked loci. The time-dependent adaptive mutagenesis produces mutants which are not obtained from other mutant mechanisms.

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