4 research outputs found
Bayesian estimation of Differential Transcript Usage from RNA-seq data
Next generation sequencing allows the identification of genes consisting of
differentially expressed transcripts, a term which usually refers to changes in
the overall expression level. A specific type of differential expression is
differential transcript usage (DTU) and targets changes in the relative within
gene expression of a transcript. The contribution of this paper is to: (a)
extend the use of cjBitSeq to the DTU context, a previously introduced Bayesian
model which is originally designed for identifying changes in overall
expression levels and (b) propose a Bayesian version of DRIMSeq, a frequentist
model for inferring DTU. cjBitSeq is a read based model and performs fully
Bayesian inference by MCMC sampling on the space of latent state of each
transcript per gene. BayesDRIMSeq is a count based model and estimates the
Bayes Factor of a DTU model against a null model using Laplace's approximation.
The proposed models are benchmarked against the existing ones using a recent
independent simulation study as well as a real RNA-seq dataset. Our results
suggest that the Bayesian methods exhibit similar performance with DRIMSeq in
terms of precision/recall but offer better calibration of False Discovery Rate.Comment: Revised version, accepted to Statistical Applications in Genetics and
Molecular Biolog
BayesBinMix: an R Package for Model Based Clustering of Multivariate Binary Data
The BayesBinMix package offers a Bayesian framework for clustering binary
data with or without missing values by fitting mixtures of multivariate
Bernoulli distributions with an unknown number of components. It allows the
joint estimation of the number of clusters and model parameters using Markov
chain Monte Carlo sampling. Heated chains are run in parallel and accelerate
the convergence to the target posterior distribution. Identifiability issues
are addressed by implementing label switching algorithms. The package is
demonstrated and benchmarked against the Expectation-Maximization algorithm
using a simulation study as well as a real dataset.Comment: Accepted to the R Journal. The package is available on CRAN:
https://CRAN.R-project.org/package=BayesBinMi
Reversible Jump MCMC in mixtures of normal distributions with the same component means
The Bayesian estimation of a special case of mixtures of normal distributions with an unknown number of components is considered. More specifically, the case where some components may have identical means is studied. The standard Reversible Jump MCMC algorithm for the estimation of a normal mixture model consisting of components with distinct parameters naturally fails to give precise results in the case where (at least) two of the mixture components have equal means. In particular, this algorithm either tends to combine such components resulting in a posterior distribution for their number having mode at a model with fewer components than those of the true one, or overestimates the number of components. This problem is overcome by defining-for every number of components-models with different number of parameters and introducing a new move type that bridges these competing models. The proposed method is applied in conjunction with suitable modifications of the standard split-combine and birth-death moves for updating the number of components. The method is illustrated by using two simulated datasets and the well-known galaxy dataset.