The aim of the statistical bioinformatics seminar is to provide a forum for people working within the broad area of computation and statistics and their application to various aspects of biology to present their work and showcase their ongoing projects. It is intended to foster the exchange of ideas and build potential collaborations across multiple disciplines. The seminars will be held at 1:00 pm on Mondays at the Charles Perkins Centre, Seminar Room (Level 3, large meeting room). The format of the talk is 30~45 minutes plus questions. ’Meet and Greet’ and afternoon tea with the speaker This year, we will have a chance for further discussion between audience members and the seminar speakers in the following hour of the seminar (2:00 pm), with some light afternoon tea. Monday April 9, 2018 1:00 PM Seminar 2:00 PM Meet and Greet with the speaker Level 3 Large Meeting Room Charles Perkins Centre Speaker: Shila Ghazanfar (The University of Sydney) Title: Investigating combinatorial expression of delta-protocadherins in single olfactory sensory neurons Abstract: Single cell RNA-Sequencing (scRNA-Seq) has enabled unprecedented insight into the behaviour of individual cells on the scale of the entire transcriptome. Such precision offers an opportunity to explore cell-specific heterogeneity, however two distinct features arise from such data: (1) hyperinflation of identically zero counts for the majority of genes for any given cell, and (2) an apparent bimodal distribution of non-zero counts. Both features are unique to scRNA-Seq, and warrant further development of statistical tools in order to answer biological questions of interest. We propose a mixture modelling framework to classify cells into three transcriptional states for each gene: (1) no, (2) low, and (3) high gene expression. This approach has the potential to reveal the cell-specific dynamics of RNA transcription (bursting) and degradation, as well as acting as a cross-dataset standardisation. We utilised a number of publicly available scRNA-Seq datasets, stemming from mouse neuronal cell populations, to perform the mixture model comparison, assess highly and lowly variable genes, and to estimate cell networks via a uniqueness thresholding. This work is in the context of understanding how olfactory sensory neurons (OSNs) interact with each other during embryonic development of the mouse olfaction system. In particular, we study the role that combinatorial expression of genes in the delta protocadherin gene subfamily plays in mediating cell-cell adhesion. Further, we utilise distinct guiding principles to build a Monte Carlo simulation of this cell-cell adhesion behaviour, and assess it’s suitability. This addresses the larger question of how combinatorial gene expression specifies specific cell types and tissues. About the speaker: Shila Ghazanfar has recently completed her PhD in Statistical Bioinformatics at The University of Sydney and is currently a Research Associate in the Judith and David Coffey Lifelab at the Charles Perkins Centre and School of Mathematics and Statistics. Her research interests are in statistical analysis of data arising from high throughput sequencing technologies such as RNA-Seq in various research contexts.