A gene is both the basic physical unit and the fundamental functional unit of heredity. DNA makes up the genes of a cell. Some genes’ primary function is to provide instructions for the production of molecules called proteins. However, there are many genes that do not code for any proteins. The length of a gene may vary anywhere from a few hundred DNA bases to more than 2 million bases in humans.
DNA molecules are present in both brain cells and skin cells, and both types of DNA molecules carry the same information about a person’s genetic makeup. The process of controlling which genes in the DNA of a cell is actually expressed is referred to as gene regulation. Even though the DNA in each cell in a multicellular creature is the same, the genes that are expressed by the various cells might be substantially different from one another.
The collection of genes that are expressed in a cell will determine the proteins and functional RNAs the cell will produce, which in turn will determine the cell’s unique characteristics. Each cell in our body includes the same genes, but some of those genes are active inside that cell while others are dormant.
Although every cell in our body contains the same genes, some genes are active while others are dormant. They are capable to generating proteins even when genes are present in the system. Gene expression refers to this particular method. Genes that are not actively being used produce no proteins and are thus considered quiet. Even when given the exact identical instructions, one cell may differentiate into a brain cell while another cell can become a skin cell.
All of the cells in an adult’s body have the same DNA, which is short for genetic composition. When compared to other cells, brain cells have the same DNA as skin cells, therefore how is it that certain cells develop into brain cells while others develop into skin cells? What causes this to occur?
During the process of cell specialization, only certain genes are “switched on” in each cell type, which causes them to be transcribed into RNA and then translated into proteins. The inactivity of the other genes is not affected. This means that genes that are active in the neurons could not be active in the cells of the skin.
For example, the genes that code for actin and myosin filaments are present in every animal cell, but muscle cells are where these genes are most actively expressed. The production of some proteins, such as antibodies in plasma cells or hemoglobin in erythrocytes, is dependent on the preferential or selective activation of certain genes during the process of cell specialization, which takes place during cell division.
Keep in mind that there are certain genes that are expressed in all different kinds of cells or genes that are necessary for the survival of all different kinds of cells, such as genes that make membranes or genes that are involved in important metabolic processes like glycolysis. Genes with this function are referred to as “housekeeping” genes.
On the other hand, “luxury genes” or “smart genes” are terms used to refer to genes that are exclusively expressed in certain kinds of cells or that express themselves in a variable manner. Genes for IgG in plasma cells; genes for opsin in the eye, which are necessary for vision (in eyes). Cells become specialized as a result of the differential expression of genes.
Following fertilization, the first cell to form, known as the zygote, contains nuclei from both gametes, but the egg is responsible for supplying all of the cytoplasms. As a result, the zygote has exclusively maternal impact genes, which are only provided by the cytoplasm of the egg. This environment is favorable for the development of the zygote. During the initial cell division, the zygotic genes that are responsible for subsequent development and differentiation are expressed.
The process of differentiating of cells is a constant phenomenon. Consider the case of neurons, which, once differentiated, maintain their state during their whole existence. Certain stimuli are responsible for inducing differentiation.
However, after they have differentiated or established themselves, these cells are no longer affected by the stimuli.
The morphological change of a cell that has already been predestined or decided is what brings about differentiation. Take a look at the graphic to see how different kinds of cells in our body each have a unique form or morphology.
In the end, differentiation is determined by elements that are genetic in nature.
Only a subset of a cell’s genes are activated, or expressed, in any given cell. The expression of the remaining genes is inhibited, also known as repressed.
Qi was able to successfully turn skin cells into brain cells by using this strategy, which is a kind of CRISPR-Cas9 gene editing. In the process, 74 novel genes that could be responsible for the transformation were discovered. This research was published in the journal Cell Stem Cell. The Qi approach modifies the primary function of CRISPR, which was to modify genes.
Does the DNA found in the cell’s brain have the same backbone as the DNA found in the cell’s skin if they both come from the same organism? a. You are correct; the backbones of all DNA molecules are identical to one another.