Introduction
Founder mutations pertain of a type of genetic change that was incorporated in the genome of a specific population through time. The population-specific genetic change associated with founder mutations are identified to cause a medical disorder hence founder mutations are often screened as soon as a particular ethnicity has been established in a patient. Examples are the C282Y and H63D founder mutations that are associated with hereditary hemochromatosis. The genetic mutation C282Y involves the genetic mutation which results in the amino acid change from cysteine (C) to tyrosine (Y) at amino acid position 282. A second genetic mutation that may also be observed in hereditary hemochromatosis is the mutation that results in the amino acid change from histidine (H) to aspartic acid (D) at amino acid position 63. These two founder mutations occur in chromosome 6 of individuals of European descent. Hereditary hemochromatosis is only observed when the two alleles of an individual carry any one of these two founder mutations. It should be understood that each gene is presented in the genome of an individual as two forms or copies, called alleles. Hereditary hemochromatosis thus will only be expressed in an individual when both alleles show founder mutations. When an individual carries a founder mutations in only one of the two alleles, hereditary hemochromatosis is not manifested but this person will show signs that his body is capable to taking in significantly higher amounts of iron than what is observed in the normal setting. To date, there are approximately 22 million individuals in the United States who are diagnosed to have hereditary hemochromatosis and this is mainly due to their ancestry, wherein their forefathers migrated from Europe and settled in the United States.
Main body
It has well been established that majority of medical diseases originate from a genetic mutation of a particular gene. Founder mutations may be considered as a type of genetic mutation because these result in a medical disorder, however, founder mutations can be distinguished from the rest of genetic mutations through the basis of its mode of transmission, wherein particular founder mutations are specifically observed only in specific human populations. These groups of individuals are thus considered to have a higher chance of carrying such genetic mutations and these genetic changes are passed on to the next generation, hence the term founder is employed in order to show that role of transmission through generations. Another distinguishing factor between simple genetic mutations and founder mutations is that individuals with genetic mutations generally live a short life span and do not life long enough to have children who might inherit the same genetic disorder. In the case of founder mutations, individuals who carry these mutations are capable of living longer lives and thus are able to marry and have children who will inherit these mutations.
Researchers have designed diagnostic assays that will help in the identification of specific founder mutations that are associated with particular medical disorders. The development of such tests are helpful because these determines which individuals carry the propensity to specific medical diseases that are caused by specific founder mutations. More importantly, these diagnostic tests are helpful in screening for these genetic diseases so that proper medical attention may be provided in order to catch the genetic disease at an early stage and therapeutic procedures could be performed at an early stage instead of treating a genetic disease that has progressed to the later stages, of which are usually untreatable and irreversible.
Mutations should be understood as changes in the deoxyribonucleic acid (DNA) sequence, which are considered the genetic structure of each human cell. Mutations may be vary in size, from the small mutations or point mutations, which involve a single nucleotide that is changed to another of the 4 nucleotides that are existing in nature, composed of adenine, guanine, cytosine and thymine. On the other, other mutations may be large, involving a few hundreds to thousands of nucleotides in length, and these are also known as chromosomal rearrangements. These large-scale rearrangements can pertain to any changes in the genetic content of a cell, from deletions or removal of a particular stretch of DNA from the entire genome, to duplications or generation of copies of the same stretch of DNA. Other chromosomal rearrangements may involve inversions, which involves the breakage and consequent reunion of a stretch of DNA within the chromosome. The inversion of a portion of a chromosome may result in a change in the expression of essential proteins of a cells and this in turn results in an imbalance in the total composition of the cell. The ultimate result of this chromosomal rearrangement is thus a delinquency of at least one protein, resulting in the abnormal functioning of the entire cell.
Conclusion
Founder mutations may also be considered as a kind of germ-line mutations because it involves the transmission of specific mutations that are passed on to the next generations. Germ-line mutations are thus modifications in the genome that are present in germ cells, which serve as the essential cells involve in reproduction, meiosis and the reassortment or recombination of genes. Each offspring thus carries a combination of genes that are derived from each of the parents, resulting in a new combination of genes that are unique to the offspring.