Single Nucleotide Polymorphisms And The Causes And Effects...

Differences in DNA exist between individuals every 1000-2000 bases in the form of single nucleotide polymorphisms (SNPs). SNPs are variation in a single nucleotide that occurs in the genome. In some cases, these SNPs have little to no consequence on a gene expression. A consequence only occurs when there is a difference in a gene expression. Sickle cell anemia is an example of a consequence of an SNPs. In the article, â€Å"Sickle Cell Anemia†, the author states the â€Å"sickle cell hemoglobin (Hb S) is formed when the amino acid valine is substituted for glutamic acid at the sixth position of the ÃŽ ² chain; this is the result of a point mutation in the gene coding for ÃŽ ² globin synthesis† (Lonergan, 2001). Although this substitution is very simple,†¦show more content†¦Wu were able to isolate genomic DNA from peripheral blood leukocytes of individuals. Wu states sickle cell anemia is the â€Å"prototype of a genetic disease caused by a single base-pair mu tation and A T transversion in the sequence encoding codon 6 of the human -globin gene† (Wu 1989). Generally, a homozygous sickle cell anemia is when â€Å"the substitution of a single amino acid in the -globin subunit of hemoglobin results in a reduced solubility of the deoxyhemoglobin molecule and erythrocytes assume irregular shapes† (Wu 1998). The DNA from each individual was subjected to â€Å"25 rounds of PDR using either the sickle cell-specific primer set (H14S and BGP2) or the normal gene-specific primer set (H14A and BGP2) using an annealing temperature† (Wu 1989). The research, Wu and his colleges conducted in 1989, has improved the technology of diagnosing sickle cell anemia by exercising easily acceptable applications, requiring a small amount of DNA, and utilizing time. Seeing that geneticists were able to analyze the characteristics of sickle cell anemia, geneticists were also able to establish the causation of severe variation between sickle cell anemia. On chromosome 11 near the -globin gene, there are clusters of several other globin genes located on chromosome 11. These -globin clusters contain a variable amount of DNA, which are referred to as haplotypes. A haplotype is a combination of DNA markers on a particular chromosome and is a form of a SNPs. Only