Gene expression

What is Gene Expression and what factors may affect it?

The practice of monitoring the activity (expression) of numerous genes at once to comprehend biological processes is known as gene expression profiling. This study makes it easier for researchers to pinpoint the molecular causes of phenotypic variations and also makes it possible to choose specific genes for future research investigations. SAGE (serial analysis of gene expression), microarray analysis, Real Time PCR-based gene expression profiling, transcriptome sequencing, as well as other methods are among the different analytic techniques used for gene expression. Certain significant factors affecting gene expression

Genomic Imprinting

When genetic material is inherited either from the mother or the father, it is expressed differently, a process known as genomic imprinting. Both the maternal and paternal alleles are expressed in the majority of autosomes. Only the paternal or the maternal allele can express an allele in less than 1% of cases, though. For instance, only the paternal allele generally contributes to the production of the insulin-like growth factor 2 gene.

Effects that occur naturally during gamete development often dictate genomic imprinting. Different levels of expression of certain maternal or even paternal alleles may result from DNA changes like methylation. If genetic inheritance prevents the causal allele from being expressed, a condition may seem to skip a generation. Clinical illnesses, such as Prader-Willi syndrome and Angelman syndrome, can be caused by defective imprinting, which can result in aberrant allele activation or silencing.

The Environment can affect the Phenotype

Scientists have long recognized environmental influences on the development of animal features. Environmental elements can change which genes in an animal are expressed, which in turn impacts the phenotype of the animals. These environmental variables include nutrition,  humidity, temperature, oxygen levels, light cycles, as well as the presence of mutagens. This is why researchers who investigate the genetics of hypothetical organisms typically aim to reduce environmental effects by observing the species under consistent investigation. It is noteworthy that even genetically identical species treated to well controlled experimental conditions may have varied phenotypes illustrates the capacity of slight environmental differences on gene expression.

Sex-limited Inheritance

Sex-limited traits are those that only exist in one sex. X-linked inheritance, which typically refers to features on the X chromosome, is different from sex-limited inheritance. When a gene’s expressivity and penetrance are altered by sex hormones along with other physiological changes between males and females, this phenomenon is known as sex-limited inheritance, which is more accurately referred to as sex-influenced inheritance. For instance, male-pattern baldness, also known as premature balding, is an autosomal dominant feature, yet it seldom manifests in females and typically only does so after menopause.


The process of using a gene’s information to create a functioning gene product is known as gene expression. Although these are frequently proteins, non-protein coding genes like rRNA or tRNA produce functional RNAs as their result. Prokaryotic as well as eukaryotic cells carefully control how genes are expressed. Cell differentiation may be influenced by internal causes. Gene expression may be impacted by the unequal distribution of mRNA, proteins, and organelles inside a cell. By transmitting and receiving signal molecules, the cells in the vicinity can have an impact on one another.