What is a bimodal distribution in biology?
a statistical pattern in which the frequencies of values in a sample have two distinct peaks, even though parts of the distribution may overlap. For example, the sexual differences between men and women for such characters as height and weight produce a bimodal distribution.
Is gene expression data normally distributed?
Gene Expression Data are not Normally-Distributed First, this behavior may be (arguably) predicted by the central limit theorem [16].
What causes increased gene expression?
Gene expression is influenced by numerous factors, including molecules within the cell, mutations causing dominant negative effects and haploinsufficiency, signaling molecules from surrounding cells and the environment, and epistasis. Various molecules within the cell modulate gene expression.
Which among the following is a bimodal distribution?
Explanation: For example, {1,2,3,3,3,5,8,12,12,12,12,18} is bimodal with both 3 and 12 as separate distinct modes.
Is RNA Seq data normally distributed?
Many genes will have a normal distribution, due to not being differentially expressed in any of the samples. Others will have a skew, typically due to a floor effect. Others will have a bimodal or multimodal distribution, due to being up/down-regulated in some cancer types.
What is Gene distribution?
Genes are distributed unevenly along the chromosomes, often organized in clusters of varying sizes and gene-densities (gene-rich regions). The regions corresponding to gene-clusters in smaller genome plants such as rice may be divided into many ‘mini’ gene-clusters in the related larger genomes.
What happens when gene expression is changed?
While genetic changes can alter which protein is made, epigenetic changes affect gene expression to turn genes “on” and “off.” Since your environment and behaviors, such as diet and exercise, can result in epigenetic changes, it is easy to see the connection between your genes and your behaviors and environment.
Can you change gene expression?
Several genetic or epigenetic events can alter gene expression and we assess their importance in multistage carcinogenesis. Mutation and chromosome rearrangement can produce changes in DNA sequence which have been identified in some cancer cells.
What does overexpression mean?
(OH-ver-ek-SPRES) In biology, to make too many copies of a protein or other substance. Overexpression of certain proteins or other substances may play a role in cancer development.
What are the two stages of gene expression?
It consists of two major steps: transcription and translation. Together, transcription and translation are known as gene expression. During the process of transcription, the information stored in a gene’s DNA is passed to a similar molecule called RNA (ribonucleic acid) in the cell nucleus.
What is bimodal gene expression?
Bimodal gene expression (the distribution of gene products that has two maxima) is a cause of phenotypic diversity in genetically identical cell populations, and it is critical for population survival in a fluctuating environment ( 1 – 4 ). Several mechanisms underlying the bimodality have been identified to date:
What is the use of bimodality index?
Bimodality index has been used in various experiments. It was shown that genes with polycomb repressive complex (PRC) histone modifications and active RNA polymerase II (RNAPII) have more bimodal gene expression patterns than genes with only active RNAPII but no PRC histone marks [64].
How do you test if the distribution is bimodal?
If the observed distribution is bimodal, the dip statistic will take on a large value. Hartigan and Hartigan thoroughly describe the statistical basis of the dip statistic, and in practice, the test can be implemented via an algorithm [16].
Why are bimodally expressed genes useful for stratification?
Bimodally expressed genes are useful for stratification and personalized medicine. Standard methods for detecting cancer-associated genes rely on comparison of sample means between cancer patients and healthy controls.