Robust Inference for the Bivariate Bifurcating Autoregressive Model

Cell lineage data consist of observations on quantitative characteristics of the descendants of an initial cell, recorded as a tree so that the relationships between the cells may be determined. The bifurcating autoregressive model of Cowan & Staudte (1986) has been used previously to model univariate characteristics of cell linkage data. Here we extend this model to analyze bivariate cell data. Both maximum likelihood and robust estimators are derived for both balanced and unbalanced cell lineage trees and are applied to a real dataset to estimate the correlation between cell lifetime and final cell diameter.