Genetics Information Resources
Genetics
Genetics is the science of heredity and the observation of similarities and
differences between living organisms. Although this is not a ‘new’ science
in itself, the field of genetics is a relatively recent development.
The
birth of modern genetic science can be attributed to the publication of
Charles Darwin’s theory of evolution in 1859. His ideas claim that evolution
occurs through the process of natural selection over many generations. Just
six years later, Gregor Mendel described how specific genetic traits could
be passed down through inheritance.
A science of genetics followed Mendel’s
discoveries, and in 1909, the term ‘gene’ was coined by William Johannssen
to describe Mendel’s units of heredity. In the 1910’s, primitive
understandings of inheritance were established; that genes are arranged
along cellular structures called chromosomes in a linear fashion.
By the
middle of the century, it was known that a long molecule called DNA was at
the core of the chromosome, and that genes existed as sections within the
molecule. Hereditary information is coded within the sequences of
nucleotides that make up the DNA strands.
Geneticists Watson and Crick found that DNA was a three-dimensional
structure in the form of a double helix. They also found that nucleotides of
each of the two DNA strands would exactly match the corresponding strand. It
is now understood that each DNA strand acts as a guide for synthesis of a
new partner strand – this is the physical inheritance mechanism.
The most
famous genetic achievement is undoubtedly the deciphering of the human
genome, however genetic understandings have also transformed the spheres of
biology, medicine, zoology and agriculture beyond recognition.
Genetic engineering is the ability to design new genetic sequences and have
these inserted into various organisms from bacteria to plants and animals.
One application of genetic engineering could be ‘gene therapy’, where
healthy copies of genes are supplied to patients suffering from conditions
caused by genetic mutation.
Genetically engineered vaccines have been
produced which stimulate the immune system by using genetic fragments of
deadly microbes. Genetic modification has also been widely utilised in the
production of crops and foodstuffs. The GM crops can be modified to be
resilient to disease or extremes of weather, whilst producing a greater
yield.
Geneticists continually find themselves at the centre of highly
controversial issues within society. Recent scares over designer babies have
resulted from the successful mapping of the human genome. Concerns over the
safety and ethical integrity of GM food production have also been at the
forefront of the critique of the discipline.
These issues can arise because
of widely held notions of ‘genetic destiny’, that by understanding the
genetic makeup of an organism, that disease can be cured. This situation is
far from coming to fruition in the near future.
It must also be noted that
even if certain diseases could be identified within the womb or at embryonic
stage, this is not a solution in itself. The outcome for that child will be
determined by complex social, moral, ethical, political and philosophical
considerations that lie apart from the genetic sphere. |
