Are you a Biology student? Then you probably have heard of the word Genetics. And if you haven’t yet, read further to find out what Genetics is all about.
Generally, organisms reproduce their kinds (Species, offspring or progeny) and never a different species. Thus, there exists a close relationship between parents and their offsprings.
The study of the similarities and differences or variations between parents and progeny or offsprings is termed Inheritance or heredity. And the science of heredity is known as Genetics.
What is genetics?
Genetics is the study of heredity. Heredity is a biological process whereby a parent passes certain genes onto their children or offspring. Every child inherits genes from both of their biological parents and these genes, in turn, express specific traits.[1]
In other words, Genetics is a branch of biology concerned with the study of genes, genetic variation, and heredity in organisms.[2]
The similarities between parents and offsprings suggest that some internal substances or factors are transported from parents to progeny in the gametes during reproduction. These factors are known as genes.
What is a Gene?
A gene is an internal factor which determines, control or influences the physical, morphological or physiological characters of all living organisms. Hence, genes are a unit of heredity in organisms and are usually carried in chromosomes(heredity vehicles).
Genome
A genome is the sum total of genes carried on chromosomes and controls all traits in an organism. Variations exist between parents and offsprings and these variations can either be continueous ordiscontinueous.
A continueous variation (height, weight, lenght, etc) usually presents intermediate individuals and is infludenced by environmental factors. That is, a continueouss variations is caused bu the influence of the environment on genes.
On the other hand, a discontinueous (the sex of an individual) variation doesn’t presnt any intermediate individuals. This type of genetic variation is only due to the influence of genes and are transmitted via successful generations.
The reason for studying this science
Genetics as a science seeks to know:
- The nature of genes (genetic material)
- How genes are transmitted from parents to offsprings through successive generations.
- How genes work. That is, the influence they have on the traits of an organism.
The history of genetics
The observation that living things inherit traits from their parents has been used since prehistoric times to improve crop plants and animals through selective breeding.
The modern science of genetics, seeking to understand this process, began with the work of the Augustinian friar Gregor Mendel in the mid-19th century (1822 – 1884)
Classical genetics
Mendel observed sharply contrasting and clearly defined characters in the garden pear and carried out breeding experiments (pants hybridisation experiments) to determine how these characteristics were transferred from parents to offspring and described the results mathematically.
Although this pattern of inheritance could only be observed for a few traits, Mendel’s work suggested that heredity was particulate, not acquired and that the inheritance patterns of many traits could be explained through simple rules and ratios.[3]
Breeding or hybridation
A breeding or hybridisation experiment involves the artificial reproduction of an organism with defined characters.
In Mendel’s pear experiment, this entails the isolation of pure breed parents with a given pair of contrasting characters.
Monohybrid inheritance
This is the study of inheritance of one pair of contrasting characters only. For example the lenght of a stem (short or tall), form of seeds(smooth or rinkle).
Molecular genetics
Molecular genetics is the study of the molecular structure of DNA, its cellular activities (including its replication), and its influence in determining the overall makeup of an organism.
Molecular genetics relies heavily on genetic engineering (recombinant DNA technology), which can be used to modify organisms by adding foreign DNA, thereby forming transgenic organisms.
Since the early 1980s, these techniques have been used extensively in basic biological research and are also fundamental to the biotechnology industry, which is devoted to the manufacture of agricultural and medical products. Transgenesis forms the basis of gene therapy, the attempt to cure genetic disease by addition of normally functioning genes from exogenous sources.
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