Multivariate analysis of Pleurodeles waltl injection outcomes using FAMD FactoMineR (RStudio 4.3.2) used to probe sources of variability during an Adeno-associated viral (AAV) screen

In this study, we analyzed the efficiency of different adeno-associated
viral (AAV) injections in transfecting neurons in the
salamander Pleurodeles waltl. To query sources of variation in
AAV injection outcomes, we analyzed metadata and outcomes for an
additional 68 intraparenchymal injections performed 39 in post-metamorphic
Pleurodeles salamanders. This dataset included both quantitative variables
(age, weight, viral genomes (v.g.) injected, and a cell transduction score
ranging from 0 to 4, see STAR Methods) and categorical variables (here
referred to as qualitative variables: serotype, promoter, reporter, single
vs. dual injection, manufacturer, and injection site). To assess the
associations between these variables, we performed a Factor Analysis for
Mixed Data (FAMD), a principal component method that is designed to
determine significant sources of variability within datasets that contain
both quantitative and qualitative data types. This dataset
contains the injection outcomes and metadata for AAV injections
administered in the salamander Pleurodeles waltl. The
RactoMineR package (https://CRAN.R-project.org/package=FactoMineR) was
used to determine significant contributions of a number of variables
contributing to injection outcomes. Analysis of these data revealed that,
among other factors, age co-varies with injection score. Therefore, we
conclude that increased animal age decreases the efficacy of this tool.