Multiple alleles
Gene expression could also be known as gene transcription, as the process almost always involves transcribing genes into RNA and/or protein types.
Constitutive gene expression refers to genes that are constantly active and produce proteins at a steady rate in a cell. This type of gene expression is not influenced by external factors or signals. In contrast, other types of gene regulation involve genes that are turned on or off in response to specific signals or conditions in the cell's environment.
An example of a gene with three or more alleles for a single trait is the ABO blood group gene. This gene has three main alleles - A, B, and O - which determine blood type. The different combinations of these alleles result in the various blood types (A, B, AB, and O) observed in humans.
An example of a single gene with multiple alleles is the ABO blood group gene. This gene has three main alleles: A, B, and O, which determine an individual's blood type. Different combinations of these alleles result in the four blood types: A, B, AB, and O.
The expression of a gene is called the phenotype.
gene expression occurring at transcription
In the process of gene expression, the gene codes for protein.
A gene with multiple alleles can produce more than three phenotypes because each allele can result in a different blood type. In the ABO blood group system, there are three alleles (IA, IB, i) that determine the presence of antigens on red blood cells, leading to four possible blood types (A, B, AB, O). The combination and expression of these alleles determine the individual's blood type phenotype.
Differential gene expression refers to the phenomenon where the level of expression of a gene can vary between different cells, tissues, or organisms. This variability can lead to distinct phenotypic differences, such as the development of specialized cell types or response to environmental stimuli. Studying differential gene expression is important for understanding how genes function and how organisms develop and respond to their surroundings.
Researchers in molecular biology often investigate questions related to how genes are turned on or off, how different factors regulate gene expression, how gene mutations affect protein production, and how gene expression patterns vary in different cell types or under different conditions.
Genes can produce visible body types, for example, hair color, eye color, height, skin color, and various other things. Most genes do not have such an easily observable result, but if there is any observable result at all, even one that you would have to observe with a microscope, then that is the outward expression of that gene.