Download charles darwin theory of evolution and mordern genetic engineering

Journal of Pharmaceutical Research and Opinion 1: 7 (2011) 174 – 177.
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JOURNAL OF PHARMACEUTICAL RESEARCH AND OPINION
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REVIEW
CHARLES DARWIN THEORY OF EVOLUTION AND MORDERN GENETIC
ENGINEERING
Abalaka M.E, Abbey F.K*
Department of Microbiology,Federal University of Technology, Minna,Nigeria.
ARTICLE INFO
ABSTRACT
Received 15 Nov 2011
Accepted 09 Dec 2011
Evolution is any change across successive generations in the heritable
characteristics of biological populations. Evolutionary processes give rise to diversity
at every level of biological organisation, including species, individual organisms and
molecules such as DNA and proteins(Hall, B. K et al,2008).Organisms could evolve
from one form to another as a result of changes in environment and genetic
information which results in variations. As variations and adaptive changes continue
over a long period of time, these give rise to diversity of form, structure and function
in organisms. This is organic evolution(Mayr E. 1982). The theories of evolution
attempt a biological explanation of the diversity of form, structure and function
among organisms. Charles Darwin (1859) an English naturalist proposed the theory
of evolution.(Goldschmidt,1940). He established that all species of life have
descended over time from common ancestry, and proposed the scientific theory that
this branching pattern of evolution resulted from a process that he called natural
selection. He published his theory with compelling evidence for evolution in his 1859
book On the Origin of Species. This theory had limitations which was the underlying
mechanism for hereditary. This limitation is further compounded in modern genetic
engineering which involves the direct modification of nucleic acid material of an
organism.
Corresponding Author:
Abbey F.K
Department of
Microbiology, Federal
University of Technology,
Minna, Nigeria.
[email protected]
KeyWords: Charles
Darwin’s theory, ancestors,
DNA
©2011, JPRO, All Right Reserved.
INTRODUCTION
Charles Darwin’s theory of evolution is the widely
held notion that all life is related and has descended from a
common ancestor; the birds and the bananas, the fishes
and the flowers all related. Darwin’s general theory
presumes the development of life from non-life and
stresses a purely naturalistic (undirected)”descent with
modification”(Charles Darwin,1859). That is complex
creatures evolve from more simplistic anscestors naturally
over time. In a nutshell, as random genetic mutations occur
within an organism’s
genetic code, the beneficial
mutations are preserved because they aid survival, a
process known as natural selection(Haldane,1932). These
beneficial mutations are passed on to the next generation.
Over time, beneficial mutations accumulate and the results
is an entirely different organism(not just a variation of the
original but an entirely different creature).
While Darwin’s theory of evolution is a relatively
young archetype, the evolutionary worldview itself is as old
as antiquity. Acient Greek philosophers such as
Anaximander postulated the development of life from nonlife and the evolutionary descent of man from
animal(Charles Darwin et al,1858). Charles Darwin simply
brought something new to the old philosophy, a plausible
mechanism called natural selection.(Bowler,2003) Natural
selection acts to preserve and accumulate minor
advantageous genetic mutations. Suppose a member of
species developed a functional advantage(it grew wings
and learned to fly),its offspring would inherit that
advantage and pass it to their offsprings The disadvantaged
members of the same species would gradually die out,
leaving only the superior members of the species. Natural
selection is the preservation of a functional advantage that
enables a species to compete better in the wild. Natural
selection is a naturalistic equivalent to domestic
breeding.(Fisher,1930) Over the centuries, human breeders
have produced dramatic changes in domestic animal
populations by selecting individuals to breed. Breeders
eliminate undersirable traits gradually over time. Similarly,
natural selection eliminates inferior species gradually over
time.Darwin’s theory of evolution is a slow and gradual
process.(Herbert, 1991) Natural selection is believed to
take advantage of slight successive variations; it can never
take a great and sudden leap but must advance by short
and sure through small steps. Darwin conceded that if it
could be demonstrated that any organ existed, which could
not possibly have been formed by numerous successive
slight modifications, his theory would break down. Such a
complex organ would be known as an irreducibly complex
system.(Darwin et al,1858) An irreducibly complex system
is one composed of multiple parts all of which are
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necessary for the system to function. (Owen, et al,2006
)Richard. Even if one part is missing, the system will fail to
function. Every individual part is integral. Thus, such a
system could not have evolved slowly piece by piece.On the
other hand,Genetic engineering also called genetic
modification is the direct human manipulation of an
organism’s genome using modern DNA technology. (Resnik
et al,2006) It involves the introduction of foreign DNA into
the organism of interest which does not require the use of
classical genetic methods.(Shukla et al,2009) an organism
that is generated through the introduction of recombinant
DNA is considered to be genetically modified. Bacteria were
the first organism to be modified in 1973 and then mice in
1974.The commonest form of genetic engineering involves
the insertion of new genetic material at an unspecified
location in the genome of the host. This is done by the
isolation and copying of the genetic material of intrest by
use of molecular cloning techniques to yield a sequence of
DNA which contains the required genetic elements or
expression and this construct is then inserted into the host
organism(David et al,2006) Genetic engineering methods
have been applied in numerous areas including research,
biotechnology and medicine. Medicines such as insulin and
some human growth hormones are now produced by
bacteria. Genetically engineered plants and animals are
capable of producing drugs which are cheaper. Genetically
engineering does not include traditional animal and plant
breeding, invitro fertilization, Induction of polyploidy,
mutagenesis and cell fusion techniques that do not use
recombinant nucleic acid or genetically modified organisms
in the process (The European Parliament and the council of
the European Union,2001). If genetic material is added to a
host, the resulting organism is said to be transgenic. If
genetic material is added from same specie or specie that
can naturally breed with the host is employed, the resulting
organism is said to be cisgenic. Humans have altered the
genome of species for thousands of years via artificial
selection and most recently mutagenesis. genetic
engineering as a direct modification of nucleic acid material
started in the 1970’s.the term genetic engineering was first
coined by jack Williamson in his novel published in
1951(Stableford,2004) a year before the role of DNA was
confirmed by Alfred Hrasley and Martha chase.Paul berg
created the first recombinant DNA by combining DNA from
monkey virus sv40 with that of lambda virus. the first
transgenic organism by the insertion of antibiotic resistant
genes into the plasmid of an e. Coli bacterium. The first
trails of genetically engineered plants occurred in France
and the USA in 1986.tobacco plants were engineered to be
resistant to herbicides(Jackson D.A,1972) In 2010,at J.craig
venter institute,scientist announced that they have created
the first synthetic bacterial genome and added it to a cell
containing no DNA. During the process of genetic
engineering, the gene to be inserted into the genetically
modified organism must be chosen and isolated. This
involves multiplying the gene through polymerase chain
reaction (PCR).The gene to be inserted must be combined
with other genetic elements to make the modification
successful. this is called construct. Most construct contain a
promoter and a terminator region as well as a selectable
marker gene. Transcription is initiated by the promoter
region and can be used to control the location and level of
gene expression. The constructs
are made using
techniques
such as restriction digest, ligations and
molecular cloning. The most common form of genetic
engineering involves inserting new genetic material at
random within the host genome(Savage et al,2007) some
techniques allow new genetic material to be inserted at
specific location in the host genome or generate mutations
at specific loci. During the process of genetic engineering,
not all cells are transformed. a selective marker is used to
differentiate transformed from non-transformed cells. The
finding that a recombinant organism contains inserted
genes is not sufficient that the genes will be expressed in an
appropriate manner in the intended tissues of the
recombinant organism. Further analysis uses techniques
like PCR,Southern hybridization,and DNA sequencing
which serve to determine the chromosomal location and
the copy number of the inserted gene.
CHARLES DARWIN’S THEORY OF EVOLUTION AND
MORDERN GENETIC ENGINEERING
Darwin’s theory of evolution is a theory in crises in
the light of the advances made in molecular biology, genetic
engineering, genetics and biochemistry over the last fifty
years( Michael Denton,1996).We know that there are infact
tens of thousands of irreducibly complex systems on the
cellular level. Specified complexity pervades the
microscopic biological world. And we don’t need
microscope to observe irreducible complexity. The eye, ear
and the heart are all examples of irreducible complexity,
though they were not recognized as such in Darwin’s day.
Darwin came to understand that any population consists of
individuals that are slightly different from one another.
Those individuals that have a variation that gives them an
advantage in staying alive long enough to reproduce are the
ones that pass on their traits more frequently to the next
generation. Subsequently, these traits become more and
more common and the population evolves. Darwin called
this ‘Descent with modification’ Darwin did not believe that
the environment was producing variation. He correctly
thought that the variation already existed and that nature
just selected for the most suitable beak shape and against
less useful ones. By the late 1860’s Darwin came to
describe this process as survival of the fittest. This is very
different from Larmarks
incorrect idea that the
environment altered the shape of individuals and that these
acquired changes were then inherited. An example of
evolution arising from natural selection was discovered
among peppered moths living near the English industrial
cities. These insects have varieties that vary in wing and
body coloration from light to dark. During the 19th century,
sooty smoke from coal burning furnaces killed lichen on
trees and darkened the bark. When moths landed on these
trees and other blackened surfaces, the dark coloured ones
were harder to spot by birds who ate them and,
subsequently, they more often lived long to reproduce over
generations. Charles Darwin’s theory hinges on his belief
that new organisms are formed as a result of evolutionary
changes occurring as a result of adaptation for survival,
recent advances in genetics outside genetic engineering
shows that the basis of hereditary is the gene which
contains genetic materials(DNA).while genetics and genetic
engineering is based on genes and DNA (genetic
materials),charles Darwin theory of evolution has no basis
on genetic materials. charles Darwin based his theory on
the fact that complex forms evolve from non complex forms
over time. His theories were based on natural selection
which acts to accumulate and transform minor
advantageous genetic mutations. Charles Darwin’s theory
of evolution is a gradual and slow process. on the other
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Abbey et. al/ Charles Darwin Theory of Evolution And Mordern Genetic Engineering
hand, modern genetic engineering is considered a fast
system which alters the underlying genetic material to
produce modifications in the new organism. Heritable
traits are known to be passed from one generation to the
next via DNA, a molecule that encodes genetic information.(
Ernesto et al,2006)DNA is a long polymer composed of four
types of bases. The sequence of bases along a particular
DNA molecule specifies the genetic information, in a
manner similar to a sequence of letters spelling out a
sentence. Before a cell divides, the DNA is copied, so that
each of the resulting two cells will inherit the DNA
sequence. Portions of a DNA molecule that specify a single
functional unit are called genes; different genes have
different sequences of bases. Within cells, the long strands
of DNA form condensed structures called chromosomes.
The specific location of a DNA sequence within a
chromosome is known as a locus. If the DNA sequence at a
locus varies between individuals, the different forms of this
sequence are called alleles. DNA sequences can change
through mutations, producing new alleles. If a mutation
occurs within a gene, the new allele may affect the trait that
the gene controls, altering the phenotype of the organism.
However, while this simple correspondence between an
allele and a trait works in some cases, most traits are more
complex and are controlled by multiple interacting genes.
Recent findings have confirmed important examples of
heritable changes that cannot be explained by changes to
the sequence of nucleotides in the DNA. These phenomena
are classed as epigenetic inheritance systems.DNA
methylation marking chromatin, self-sustaining metabolic
loops, gene silencing by RNA interference and the three
dimensional conformation of proteins (such as prions) are
areas where epigenetic inheritance systems have been
discovered at the organismic level.
Modern genetic engineering modifies the basis for
heritable traits(DNA) to produced modified organisms and
this heritable traits have been proven over time to be
reponsible for transmission of inheritance.( Resnik,et
al,2006) On the other hand, Charles Darwin’s theory has no
basis on any of the recent advances in genetics. Genetic
engineering gives us the advantage of producing the
organism of choice while Charles Darwin’s evolution
produces the organism of choice of the environment since
environmental and adaptation requirements are
determinants of survivors. He could not explain his theory
in a way consistent with known genetic mechanisms.
CONCLUSION
Modern genetic engineering is based on known
genetic mechanisms for the production of modified
organisms as a result of changes in the genetic materials of
the modified organism and is in contrast with Charles
Darwin’s theory of evolution which described changes in
organisms without a change in the genetic materials.
Genetic engineering though is an artificial scientific method
but Charles Darwin proposed his theory as a purely
naturalistic method.Charles Darwin’s theory does not also
match modern genetic principles because of some
irreducible complexes described in the text above.
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