How the number of alleles influences gene expression

Beata Hat, Pawel Paszek, Marek Kimmel, Kazimierz Piechor, Tomasz Lipniacki

    Research output: Contribution to journalArticlepeer-review


    The higher organisms, eukaryotes, are diploid and most of their genes have two homological copies (alleles). However, the number of alleles in a cell is not constant. In the S phase of the cell cycle all the genome is duplicated and then in the G2 phase and mitosis, which together last for several hours, most of the genes have four copies instead of two. Cancer development is, in many cases, associated with a change in allele number. Several genetic diseases are caused by haploinsufficiency: Lack of one of the alleles or its improper functioning. In the paper we consider the stochastic expression of a gene having a variable number of copies. We applied our previously developed method in which the reaction channels are split into slow (connected with change of gene state) and fast (connected with mRNA/protein synthesis/decay), the later being approximated by deterministic reaction rate equations. As a result we represent gene expression as a piecewise deterministic time-continuous Markov process, which is further related with a system of partial differential hyperbolic equations for probability density functions (pdfs) of protein distribution. The stationary pdfs are calculated analytically for haploidal gene or numerically for diploidal and tetraploidal ones. We distinguished nine classes of simultaneous activation of haploid, diploid and tetraploid genes. This allows for analysis of potential consequences of gene duplication or allele loss. We show that when gene activity is autoregulated by a positive feedback, the change in number of gene alleles may have dramatic consequences for its regulation and may not be compensated by the change of efficiency of mRNA synthesis per allele. © Springer Science+Business Media, LLC 2007.
    Original languageEnglish
    Pages (from-to)511-533
    Number of pages22
    JournalJournal of Statistical Physics
    Issue number1-2
    Publication statusPublished - Jul 2007


    • Diploid genes
    • Feedback regulation
    • Haploinsufficiency
    • Piecewise deterministic time-continuous Markov process
    • Stochastic gene expression


    Dive into the research topics of 'How the number of alleles influences gene expression'. Together they form a unique fingerprint.

    Cite this