Role of Genetics in Development
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Genetics is a branch of biology that researches the notions of genes, heredity, and development of living organisms. The subject matters of the science are genes, genetic material, variation and changes within population considering the influence of heredity. Genes have been universal units that are applied not only to human beings but also to all living organisms including bacteria, viruses, and plants. Since prehistoric times, genetics has been used to research and improve the nature of plants and animals. It helps in molding and changing generation.
The paper aims to analyze the role of genetics in the human being’s development, the way parents’ genes influence the traits of the offspring. The analysis deals with issues that cause genetic and chromosomal disorders such as Tay-Sachs disease.
Genetics in Development
Genetics researches development of living organisms from its early stages of formation. Human formation and development begins when the male reproductive cell gets through the outer membrane of the female reproductive cell and form one cell. This process is called fertilization. Both male and female reproductive cells contain chromosomes. Human body has 46 chromosomes. Each of chromosomes is a functional structure. They contain genes, which are made up of chemical structures known as deoxyribonucleic acid (DNA). DNA contains genetic information that is necessary in the process of evolution and functioning of living organisms (Berger, 2000).
A child gets two copies of genes from parents, one of which is dominant. Genes contain physical and psychological traits that are transmitted from parents to their children.
How Genes of Parents Influence Traits of Offspring
Genes of two parents influence the traits of their offspring. The set of genes that a child inherits from parents is called genotype. Genotype may include physical and psychological characteristics and traits such as height, color, confidence, certain type of temperament. There are a lot of traits that are transmitted from parents to their children. They are called hereditary traits. A child can inherit blue eyes of mother and brown hair of father. However, mixing at the genetic level leads to formation genes for a certain trait in dominant and recessive forms.
Gene’s expression depends on its interaction with other genes, interaction between genotype, and the environment. Taking into consideration that genes are inherited from two different people, they might contain conflicting information. In this regard, there is always a contradiction. For example, in case a child has one tall parent and one short parent, the child may have an average height due to the mixing processes at the genetic level. Other genes may follow a dominant-recessive approach. If one parent has a dominant gene and the other recessive gene, the dominant gene predominates. For example, one parent has dominant gene for blue eyes and the other has recessive gene for black eyes, the dominant gene for blue eyes will be transmitted to a child (Miko, 2008).
The interaction of a child with the environment, whether in the uterus or later in life, may also influence the set of genes. An example of gene-environment interaction is exposing a child to drugs. Children of drug addicted parents are at high risk of harmful influences. They are vulnerable to different kinds of disorders due to genetic information that was transmitted from their drug addicted parents. Environmental factors, for example, serious diseases or lack of nutrition may influence the trait of height. Though a child may have inherited genes for tallness from parents, the trait may be suppressed by different environmental factors.
Development and transmission of genetic information is a complex process that has different obstacles in its way. One of the obstacles is uneven division of cells. This causes the formation of less number of chromosomes. Abnormal cell fertilizes a cell with the right number of chromosomes, which causes various genetic diseases.
During the process of division, a chromosome is divided into two parts. The main part of a chromosome X plays a vital role in the process of living organisms’ development. Children should have at least one X chromosome. But in some cases, children are born with missing X chromosome or with an additional X chromosome. This leads to abnormalities such as Turner syndrome, Fragile X syndrome, and Klinefelter syndrome.
Turner syndrome is experienced when only X chromosome is present. Females are the most vulnerable to this abnormality. It prompts to the lack of full genetic information. Affected people have heart, kidney problems. Turner syndrome affects the reproductive system of females. It causes learning difficulties and influences mental abilities of human beings.
Fragile X syndrome occurs when two chromosomes attach to each other by a thin string (National Library of Medicine, 2007). It affects both boys and girls. Kleinfelter syndrome is characterized by the existence of an extra X chromosome in boys. It affects the development of secondary sex characteristics and causes difficulty in learning processes (Klinefelter, 1986).
Another type of chromosomal disorder is Down syndrome. It occurs when there are three chromosomes in the 21st chromosome instead of the normal two. Individuals with the disorder may have heart problems, hearing disabilities, and complex brain problems.
Tay-Sachs disease (TSD) was named after a physician Bernard Sachs and an ophthalmologist Warren Tay. The scientists described the first causes of disease in 1887. Tay-Sachs disease affects the nervous system of human beings. The main reason of its development is a lack of HEX A gene in babies (Centre for Genetics Education, 2007). The HEX A is responsible for breaking down toxic substances in people’s organisms. Its main function is to recycle fatty substances known as GN12 in the brain. The brain requires only a small amount of the GN12 for proper functioning. Lack of HEX A provokes accumulation of GN12 in the brain that damages its cells.
HEA X gene is found in chromosome number 15. Therefore, each body cell has two copies of HEA X gene. The existence at least of one copy of gene provides the efficient functions of organisms. HEA X enzyme will still be produced for efficient body functioning. People who have only one functioning copy of the gene are known as genetic carriers for TSD. They do not have TSD and are not affected in any way.
People affected by TSD have both copies of HEA X gene that are nonfunctional. In this regard, HEA X enzyme will not be produced, and fatty substances will not be broken down. Children inherit TSD from parents in their genes when the change in one gene is recessive, and the working gene becomes dominant. TSD prompts different kinds of mutations at the genetic level. They eliminate the functional activity of people’s organisms.
When both parents are carriers of the faulty gene, they have 1 chance in 4 (or 25% chance) in every pregnancy of having a child with TSD. If only one parent is a carrier of the faulty gene, they will not have a child with TSD. Genetic testing may be available pre-pregnancy and in pregnancy and is appropriate when there is a family history, or a blood relative is a genetic carrier for these conditions. When both parents are genetic carriers of the same genetic condition, they can find out information about the condition and their chance of having an affected child and discuss their reproductive options with a genetic counselor (Centre for Genetics Education, 2007).
Every cell of the human organism contains approximately 24,000 genes that possess certain information necessary for effective functioning of all human resources and mechanisms. Genes determine all physical and psychological characteristics of an individual. They show characteristic patterns of inheritance as they are passed through generations, depending on whether their expression is dominant or recessive, and whether or not they are located on the sex chromosomes. Each child of a parent with a dominantly expressed condition has a 50 per cent chance of inheriting that condition.
The lack of full genetic information, mutations at the genetic level can cause the development of different abnormalities and diseases that can be transmitted from parents to their children. Knowledge and understanding of basic genetic concepts assist in predicting risks of disease transmission at the genetic level and development of abnormalities in the human organism.
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