Genetic Architecture of the Hippocampal Mossy Fiber Subfields in the BXD RI Mouse Strain Series: A Preliminary QTL Analysis

Abstract

The recombinant inbred (RI) strain methodology has been used to analyze the genetic architecture of the size of the different hippocampal mossy fiber layers. The study has been performed on the whole set of the 26 RI strains of the BXD series. Heritability estimates ranging from 36 to 66% indicated a rather high contribution of the additive genetic component to the variation seen. A preliminary QTL analysis, performed by interval mapping, showed that the proportion of the CA3–CA4 synaptic field covered by the different mossy fiber layers was controlled by independent, suggestive QTLs. Single or multilocus R2 estimates showed that models with one to three suggestive QTLs could explain 63 to 92% of the variance of the mossy fiber layers, although no QTL was identified for the suprapyramidal layer. On the whole, the results of the QTL analysis indicate that the proportion of synapses in the different mossy fiber layers is largely under genetic control.