Human Inheritance, Essay Example

Many scientists and genetic researchers are now convinced that development in human beings in based almost entirely on inheritance which H.E. Walter defines as the “acquisition or expression of traits or conditions via the transmission of genetic material,” such as chromosomes and DNA, “from parents to offspring” (2010, p. 45). Genetically speaking, human development encompasses a gradual process of change and differentiation from a simple to a more advanced level of complexity which includes physical, emotional, and mental capacities. This process also involves a series of complex adaptations to the environment which many researchers see as indelibly linked to genetics and heredity.

There are basically three types of inherited traits that are passed down from one generation to another–1), dominant traits which are inherited characteristics like eye and hair color from either one parent or both via dominant genes which produce a phenotypic effect regardless of whether its allele, being “one or more alternative forms of a gene,” is the same or different” (Walter, 2010, p. 163); 2), recessive traits or genetically determined characteristics via recessive genes which “lack the ability to express themselves in the presence of more dominant allele” (Walter, 2010, p. 167); and 3), sex-linked traits or genes that transmit normal or abnormal characteristics or conditions and which are carried on the sex chromosomes, specifically the X chromosome that appears “singly in the cells of normal males and in duplicate in the cells of normal females” (Walter, 2010, p. 173). These sex-linked genes are closely linked to sex-limited genes or autosomal genetic traits or conditions that are expressed in only one sex, although the genes for them may be carried by both parents.

References

Walter, H.E. (2010). Genetics: An introduction to the study of heredity. New York: Kessinger Publishing.