Man, in all his uniqueness, has managed to conquer the world and its inhabitants for thousands of millennia now. Animals and plants have their own unique characteristics too, at least scientifically as well as biologically.
Scientists and other theorists have been working round the clock to understand the origins and nature of these unique characteristics found in both primate and non-primate organisms (Lahn & Ebenstein, 2008). Below, several concepts that are thought to cause genetic diversity are critically evaluated in a bid to offer answers to the myriad of questions on the unique characteristics prevalent in organisms.
Genetic diversity is a term mostly used to underscore the “variation in the nucleotides, genes, chromosomes, or whole genomes of organisms” (Harrison et al, 2004, para. 1). In its most straightforward level, genetic diversity is characterized by variations in the nucleotides, the basic ingredients that forms the DNA contained in the cells of a living organism.
The chromosomes residing within the organism’s cells play host to the DNA. Most organisms contain two sets of chromosomes, with a few exceptions that have one, three, or four pairs of chromosomes in a cell. If an organism is diploid (two sets of chromosomes), it means that it has two alleles of each gene (Harrison et al, 2004).
Mutation and sexual reproduction comes in since there are the major factors that lead to variation of either one or more alleles contained in each gene (Lewontin, 1995; Harrison et al, 2004). Other biologists and anthropologists are of the opinion that geographical localities and lifestyles are also possible candidates for genetic diversity in primates.
Generally, mutations are changes in the structure of the DNA which form the foundation for dissimilarities between related organisms (Lewontin, 1995; TutorVista.com, 2008). Although a single mutation can have an overbearing effect on an organism, most evolutionary variations and spontaneous mutations are as a result of accrual of many mutations in the natural setting.
One of the fundamental objectives of all living creatures is to survive. It is therefore imperative for cells to continue reproducing so that the objective can be met (Knight, 2009). During sexual reproduction, an organism inherits alleles from the sperm and ova of both parents.
The pairing or copying of these alleles after fertilization to form an offspring can assist to introduce genetic variation which may indeed be of great benefit in the future. This process is called sexual recombination (Harrison et al, 2004; Knight, 2009). An example of such genetic variation can be witnessed in the difference in looks between an offspring and its parents.
Sexual reproduction introduces the issues of migration and population size. Migration is the progression or movement, in most cases within organisms (USDA, 2006). The chromosomes inherited by the offspring from the parents are bound to change more if there has been a case of migration or hybridization (Harrison et al, 2004).
This is especially so if parents of the offspring happen to come from different populations, and therefore posses dissimilar gene pools. In plants, genetic diversity via migration takes place through pollen dispersal or grafting of vegetative stems.
Lastly, sexual reproduction, in altering genetic diversity, allows organisms to increase their population size with the aim of maintaining a high competitive advantage over the others (Harrison et al, 2004). This is crucial for survival. Sexual reproduction has the capacity to introduce new and more advanced gene into a population.
The essence of this type of gene shuffling is yet another fundamental foundation for genetic diversity. It cannot escape mention that genetic variation also occurs when alleles of two or more sets of populations mix through migration incase of primates or via pollen and seed dispersal via non-primates (USDA, 2006). It is therefore true to say that genetic diversity is in a constant mode of change – both through time and across geographical localities.
Harrison, I., Laverty, M., & Sterling, E. (2004). Genetic Diversity. Retrieved February 5 2010
Knight, J.C. (2009). Human Genetic Diversity: Functional Consequences for Health and Disease: Oxford University Press. ISBN: 9780199227693
Lahn, B.T., & Ebenstein, L. (2008). Let’s celebrate human genetic diversity. Nature, Vol. 461, pp. 726-728
Lewontin, R. (1995). Human Diversity, 2nd Ed. W.H. Freeman & Company. ISBN: 0716760134
United States Department of Agriculture. (2006). Why is Genetic Diversity always Changing? Retrieved February 5 2010