INTRODUCTION TO THE CONCEPT OF GENOMICS

1. Introduction to the concept of Genomics
Presented by:
April Mae C. Quiapo
Genetics: study of inherited phenotypes.
Genomics: study of genomes.
Biochemistry: study of the chemistry of living organisms and/or cells.
Genomes and Genomics
• The word “genome,” coined by
German botanist Hans Winkler in
1920, was derived simply by
combining gene and the final
syllable of chromosome.
• If not specified, “genome” usually
refers to the nuclear genome!
• An organism’s genome is defined as
the complete haploid genetic
complement of a typical cell.
• The genetic content of the organelles
in the cell, is not considered part of
the nuclear genome.
• In diploid organisms, sequence
variations exist between the two
copies of each chromosome present
in a cell.
• The genome is the ultimate source
of information about an organism.
• The number of genomes sequenced
in their entirety is now in the
thousands and includes organisms
ranging from bacteria to mammals.
• The first complete genome to be
sequenced was that of the bacterium
Haemophilus influenzae, in 1995.
• The first eukaryotic genome
sequence, that of the yeast
Saccharomyces cerevisiae, followed
in 1996.
• The genome sequence for the
bacterium Escherichia coli became
available in 1997 .
• The much larger effort directed at the
human genome was also
accelerating.
"Genes" are units of genetic information present on the DNA in the chromosomes and
chromatin.
" Genome" is all the DNA contained in an organism or a cell, which includes the chromosomes
plus the DNA in mitochondria (and DNA in the chloroplasts of plant cells).
What Is Functional Genomics?
The goal of functional genomics is to understand the relationship between an organism’s genome
and its phenotype.
 a field of molecular biology that is attempting to make use of the vast wealth of data
produced by genome sequencing projects to describe genome function.
 uses high-through put techniques like DNA microarrays, proteomics, epigenomics,
metagenomics, metabolomics and mutation analysis to describe the function and
interactions of genes.
The genomic revolution Gene identification approaches
 Human genome sequence
 High-throughput technologies
 Large human biobanks
 Biostatistics & Bioinformatics
 Genome-wide linkage
 Candidate gene
 Homozygosity mapping
 Full exome / genome sequencing
 Genome-wide association

2. Evolutionary genetics
Natural selection is the gradual, non-random process by which biological traits become either
more or less common in a population as a function of differential reproduction of their bearers. It
is a key mechanism of evolution. The term "natural selection" was popularized by Charles
Darwin.
Evolutionary genetics (Huxley 1942)
-advantageous mutations have been positively selected in human populations during recent
evolution
-disadvantageous mutations have been negatively selected in human populations during
recent evolution
THRIFTY GENOTYPE HYPOTHESIS:
Fatter individuals carrying the thrifty genes would thus better survive times of food scarcity.
 Obesity and type 2 diabetes predisposing mutations may show evidence of positive signature
of evolution
Applied Genetic Engineering
 Crop plants with improved nutritional qualities can be created
 Animal growth rate can be genetically engineered
 Engineered microbes can help degrade toxic waste
 The production of useful proteins is a primary impetus for recombinant DNA
Biomedical Applications
 Recombinant DNA technology is used to produce large amounts of medically important
proteins
 Animal viruses such as retroviruses may prove useful vectors for gene therapy to treat single
gene disorders
 Recombinant DNA probes detect mutant genes in hereditary disease
 A major breakthrough in disease prevention would come through the development of
synthetic vaccines produced by recombinant DNA