Parallel and Evolutionary Approaches to Computational Biology - Parallel Computing for Bioinformatics and Computational Biology - page 4

1.1 INTRODUCTION
Computational biology is the use of computational techniques to model biological
systems at various levels of complexity — atomic, metabolic, cellular, and pathologic.
The field of computational biology covers many areas: structural biology, biochem-
istry, physical chemistry, molecular biology, genomics and bioinformatics, control
theory, statistics, mathematics, and computer science. Bioinformatics provides a
wealth of potential challenges that can be used to advance the state of the art by creating
scalable applications that can be used in customer environments. Thus, in computa-
tional biology, conducting research related to the realization of parallel / distributed
scalable applications requires an understanding of the basics of all related fields.
Therefore, this chapter starts with a detailed explanation of certain technical terms
that have proved to be essential for researchers in computational biology.
1.1.1 Chromosome
A chromosome is a long string of double-stranded deoxyribonucleic acid (DNA), the
molecule that serves as a primary repository of genetic information. Thomas Hunt
Morgan found that genes on a chromosome have a remarkable statistical property,
that is, genes appear as being linearly arranged along the chromosome and also that
chromosomes can recombine and exchange genetic material. A gene is a unit of
heredity used to describe a unit of phenotype variation.
1.1.2 Allele
Alleles are alternate forms of the same gene. There may be hundreds of alleles for
a particular gene, but usually only one or a few are common. A homologous pair of
chromosomes contain two alleles, one in the chromosome derived from the father and
the other in the chromosome derived from the mother. If, for example, the chromosome
inherited from the mother has a mutant allele at a specific position, this position on
a chromosome is called a locus, and the presence of a single mutant allele creates
the trait of disease. However, the child will not suffer from the disease caused by this
mutation unless both the genes inherited from parents are defective or one of them
is on the X chromosome, for example, hemophilus. In brief, an allele is a type of the
DNA at a particular locus on a particular chromosome.
1.1.3 Recombination
Recombination or crossing over is defined as the recombination of maternal chromo-
some pairs with its paternal chromosome and exchanges material in the genesis of a
sperm or egg. This formation of new gene combination is the result of the physical
event of crossing over. The intensity of linkage of two genes can be measured by
the frequency of the recombinants. The probability that a recombination event occurs
between two loci is a function of the distance between these loci. In fact, the alleles
at two loci that are far apart on a chromosome are more likely to combine than the