Biology Reference
In-Depth Information
DNA taken a heat-killed virulent strain of the bacterium
Strepto-
coccus pneumonae
(Avery
et a
l., 1944). James Watson and Francis
Crick proposed a double helical structure for DNA in 1953 (Watson
and Crick, 1953). In 1958, Kornberg discovered and isolated DNA
polymerase in order to make DNA in a test tube. Kary Mullis and
colleagues invented a technique for multiplying DNA sequences
in
vitro
by the polymerase chain reaction (PCR) in 1980 (Mullis KB,
1990).
Diagnosis of genetic disorders is clearly the focused aim of
many research groups, since genetic disorders are an important
health problem among the world. More than 4000 genetic diseases
are known, many of which are debilitating or fatal (McKusick,
1991). Cystic fibrosis (CF), an autosomal recessive disorder, occurs
approximately once in every 3500 live births (Lommatzsch and
Aris, 2009). Exocrine glands and small airways are affected in CF
resulting in death in early twenties. Over 800 mutations leading to
CF have been found. Another example is alpha-1 antitrypsin (A1AT)
deficiency that affects approximately one in 2000 individuals. A1AT
deficiencyisaconditioninwhichtheliverdoesnotmakeenoughofa
protein that protects the lungs and liver from damage. It is the most
common genetic liver disease in children. This condition can lead
to emphysema andcholestasis, late hemorrhagic disease, orchronic
liverdisease (Fairbanks and Tavill, 2008; Gooptu
et al
., 2009).
Mutations of DNA in cells are the reason of most of the genetic
disorders. Some genetic diseases can be identified by detecting
the defective protein, product of mutated gene. However, there are
many genetic disorders that do not have a characterized change of
a protein. Moreover, many of these genetic disorders are formed
by even a single mismatch (single nucleotide polymorphism [SNP]).
SincedetectionofthesedefinedsequencesofDNAisveryimportant
for the diagnosis of these diseases, development of DNA-based
biosensorsiscrucial for correct andcost-e
cient diagnosis.
Besides the genetic diseases, there are different types of DNA
damages potentially leading diseases like cancer induced endoge-
nously by attack of reactive oxygen species or exogenously by many
different sources such as radiation, ultraviolet light, toxins, and
mutagenic chemicals. Analyzing DNA damage is vital to understand
those diseases and screening new treatments.
