How to Account for Past Selection When Maternal Effects Are Cascading.

Area of Science:

• Evolutionary biology
• Quantitative genetics
• Developmental biology

Background:

• Maternal effects describe how an individual's phenotype is influenced by its mother's phenotype.
• Cascading maternal effects involve a chain of influence, where each generation's phenotype depends on previous maternal ancestors.
• Previous quantitative genetics models assessed evolutionary consequences of these effects under pragmatic assumptions.

Purpose of the Study:

• To extend the theoretical framework for modeling cascading maternal effects.
• To incorporate selection on past maternal states within the current generation's model.
• To provide a more consistent and flexible framework for analyzing transgenerational phenotypic effects.

Main Methods:

• Development of extended quantitative genetics models.
• Inclusion of selection acting on past maternal states.
• Analysis of evolutionary dynamics, including genetic covariances between current and past states.

Main Results:

• The extended framework accounts more consistently for cascading phenotypic parental effects.
• Qualitative results of previous studies remained largely unchanged.
• Small quantitative changes were observed in evolving genetic components, offspring phenotype, and fitness.

Conclusions:

• The extended framework offers a conceptually more consistent approach to modeling parental effects.
• It captures the impact of genetic covariances between current and past states on evolutionary dynamics.
• The framework is adaptable for analyzing transgenerational influences from various ancestors.