  We present symmetry tests for bifurcating autoregressive processes (BAR) when
some data are missing. BAR processes typically model cell division data. Each
cell can be of one of two types \emph{odd} or \emph{even}. The goal of this
paper is to study the possible asymmetry between odd and even cells in a single
observed lineage. We first derive asymmetry tests for the lineage itself,
modeled by a two-type Galton-Watson process, and then derive tests for the
observed BAR process. We present applications on both simulated and real data.
