Genetic epidemiology
Encyclopedia
Genetic epidemiology is the study of the role of genetic
factors in determining health and disease in families and in populations, and the interplay of such genetic factors with environmental factors. In slightly more formal language, genetic epidemiology was defined by Morton as "a science which deals with the etiology
, distribution, and control of disease in groups of relatives and with inherited causes of disease in populations". It is closely allied to both molecular epidemiology
and statistical genetics, but these overlapping fields each have distinct emphases, societies and journals.
Traditionally, the study of the role of genetics in disease progresses through the following study designs, each answering a slightly different question:
This traditional approach has proved highly successful in identifying monogenic disorders and locating the genes responsible.
More recently, the scope of genetic epidemiology has expanded to include common diseases for which many genes each make a smaller contribution (polygenic, multifactorial or multigenic disorders). This has developed rapidly in the first decade of the 21st century following completion of the Human Genome Project
, as advances in genotyping
technology and associated reductions in cost has made it feasible to conduct large-scale genome-wide association studies
that genotype many thousands of single nucleotide polymorphism
s in thousands of individuals. These have led to the discovery of many genetic polymorphisms that influence the risk of developing many common diseases.
is the method for identifying wide spread population damage (as mercury contamination
in Minamata Bay) but a genotoxicity bioindicator is a preventive way of seeing congenital malformations epidemic in human populations.
A biological monitor, or biomonitor, is defined as an organism that provides quantitative information on the quality of the environment around it. Therefore, a good biomonitor will indicate the presence of the pollutant and also attempt to provide additional information about the amount and intensity of the exposure.
Endocrine Disruption (feminization); Reproductive Failure
causes include early embryonic death, embryo toxicity and abnormal parental behaviour during incubation; Eggshell Thinning including Double-crested Cormorants, Ospreys, Bald Eagles, Black-crowned Night-Herons and Herring Gulls, maybe are caused by pollution or another genotoxic factor.
Malformed frogs are caused by parasites, genetic disease or pollution? Crossed bills, jaw defects, extra limbs, and malformed feet, joints and eyes were found in Herring Gulls and at least eight other species of fish-eating waterbirds from great lakes, malformed frogs were found in Minnesota. (see external link below)
Genetics
Genetics , a discipline of biology, is the science of genes, heredity, and variation in living organisms....
factors in determining health and disease in families and in populations, and the interplay of such genetic factors with environmental factors. In slightly more formal language, genetic epidemiology was defined by Morton as "a science which deals with the etiology
Etiology
Etiology is the study of causation, or origination. The word is derived from the Greek , aitiologia, "giving a reason for" ....
, distribution, and control of disease in groups of relatives and with inherited causes of disease in populations". It is closely allied to both molecular epidemiology
Molecular epidemiology
Molecular epidemiology is a branch of medical science that focuses on the contribution of potential genetic and environmental risk factors, identified at the molecular level, to the etiology, distribution and prevention of disease within families and across populations. This field has emerged from...
and statistical genetics, but these overlapping fields each have distinct emphases, societies and journals.
Traditionally, the study of the role of genetics in disease progresses through the following study designs, each answering a slightly different question:
- Familial aggregation studies: Is there a genetic component to the disease, and what are the relative contributions of genes and environment?
- Segregation studies: What is the pattern of inheritanceDominance relationshipDominance in genetics is a relationship between two variant forms of a single gene, in which one allele masks the effect of the other in influencing some trait. In the simplest case, if a gene exists in two allelic forms , three combinations of alleles are possible: AA, AB, and BB...
of the disease (e.g. dominant or recessive)? - LinkageGenetic linkageGenetic linkage is the tendency of certain loci or alleles to be inherited together. Genetic loci that are physically close to one another on the same chromosome tend to stay together during meiosis, and are thus genetically linked.-Background:...
studies: On which part of which chromosomeChromosomeA chromosome is an organized structure of DNA and protein found in cells. It is a single piece of coiled DNA containing many genes, regulatory elements and other nucleotide sequences. Chromosomes also contain DNA-bound proteins, which serve to package the DNA and control its functions.Chromosomes...
is the disease gene located? - AssociationGenetic associationGenetic association is the occurrence, more often than can be readily explained by chance, of two or more traits in a population of individuals, of which at least one trait is known to be genetic....
studies: Which alleleAlleleAn allele is one of two or more forms of a gene or a genetic locus . "Allel" is an abbreviation of allelomorph. Sometimes, different alleles can result in different observable phenotypic traits, such as different pigmentation...
of which gene is associated with the disease?
This traditional approach has proved highly successful in identifying monogenic disorders and locating the genes responsible.
More recently, the scope of genetic epidemiology has expanded to include common diseases for which many genes each make a smaller contribution (polygenic, multifactorial or multigenic disorders). This has developed rapidly in the first decade of the 21st century following completion of the Human Genome Project
Human Genome Project
The Human Genome Project is an international scientific research project with a primary goal of determining the sequence of chemical base pairs which make up DNA, and of identifying and mapping the approximately 20,000–25,000 genes of the human genome from both a physical and functional...
, as advances in genotyping
Genotyping
Genotyping is the process of determining differences in the genetic make-up of an individual by examining the individual's DNA sequence using biological assays and comparing it to another individual's sequence or a reference sequence. It reveals the alleles an individual has inherited from their...
technology and associated reductions in cost has made it feasible to conduct large-scale genome-wide association studies
Genome-wide association study
In genetic epidemiology, a genome-wide association study , also known as whole genome association study , is an examination of many common genetic variants in different individuals to see if any variant is associated with a trait...
that genotype many thousands of single nucleotide polymorphism
Single nucleotide polymorphism
A single-nucleotide polymorphism is a DNA sequence variation occurring when a single nucleotide — A, T, C or G — in the genome differs between members of a biological species or paired chromosomes in an individual...
s in thousands of individuals. These have led to the discovery of many genetic polymorphisms that influence the risk of developing many common diseases.
Genotoxicity bioindicator
Cluster analysis in epidemiologyEpidemiology
Epidemiology is the study of health-event, health-characteristic, or health-determinant patterns in a population. It is the cornerstone method of public health research, and helps inform policy decisions and evidence-based medicine by identifying risk factors for disease and targets for preventive...
is the method for identifying wide spread population damage (as mercury contamination
Minamata disease
', sometimes referred to as , is a neurological syndrome caused by severe mercury poisoning. Symptoms include ataxia, numbness in the hands and feet, general muscle weakness, narrowing of the field of vision and damage to hearing and speech. In extreme cases, insanity, paralysis, coma, and death...
in Minamata Bay) but a genotoxicity bioindicator is a preventive way of seeing congenital malformations epidemic in human populations.
A biological monitor, or biomonitor, is defined as an organism that provides quantitative information on the quality of the environment around it. Therefore, a good biomonitor will indicate the presence of the pollutant and also attempt to provide additional information about the amount and intensity of the exposure.
Endocrine Disruption (feminization); Reproductive Failure
causes include early embryonic death, embryo toxicity and abnormal parental behaviour during incubation; Eggshell Thinning including Double-crested Cormorants, Ospreys, Bald Eagles, Black-crowned Night-Herons and Herring Gulls, maybe are caused by pollution or another genotoxic factor.
Malformed frogs are caused by parasites, genetic disease or pollution? Crossed bills, jaw defects, extra limbs, and malformed feet, joints and eyes were found in Herring Gulls and at least eight other species of fish-eating waterbirds from great lakes, malformed frogs were found in Minnesota. (see external link below)
See also
- ThalidomideThalidomideThalidomide was introduced as a sedative drug in the late 1950s that was typically used to cure morning sickness. In 1961, it was withdrawn due to teratogenicity and neuropathy. There is now a growing clinical interest in thalidomide, and it is introduced as an immunomodulatory agent used...
- Genetic disorderGenetic disorderA genetic disorder is an illness caused by abnormalities in genes or chromosomes, especially a condition that is present from before birth. Most genetic disorders are quite rare and affect one person in every several thousands or millions....
- Molecular epidemiologyMolecular epidemiologyMolecular epidemiology is a branch of medical science that focuses on the contribution of potential genetic and environmental risk factors, identified at the molecular level, to the etiology, distribution and prevention of disease within families and across populations. This field has emerged from...
- MutationMutationIn molecular biology and genetics, mutations are changes in a genomic sequence: the DNA sequence of a cell's genome or the DNA or RNA sequence of a virus. They can be defined as sudden and spontaneous changes in the cell. Mutations are caused by radiation, viruses, transposons and mutagenic...
- Radiation damageRadiation damageRadiation damage is a term associated with ionizing radiation.-Causes:This radiation may take several forms:*Cosmic rays and subsequent energetic particles caused by their collision with the atmosphere and other materials....
- Population geneticsPopulation geneticsPopulation genetics is the study of allele frequency distribution and change under the influence of the four main evolutionary processes: natural selection, genetic drift, mutation and gene flow. It also takes into account the factors of recombination, population subdivision and population...
- Hardy–Weinberg principle
- Population groups in biomedicine
External links
- Journal of Joint Bone Surgery 1997 Jan;79(1):58-65.
- North American Reporting Center for Amphibian Malformations (NARCAM) Jul. 2011
- Minnesota's Malformed Frogs Jul. 2011
- Studies offer new insights into causes of deformed frogs Jul. 2011
- Deformed Frogs Raise Concerns Jul. 2011
- Deformed Frog Pictures Jul. 2011
- Contaminant-related effects observed in Herring Gulls and other fish-eating waterbirds inhabiting the Great Lakes.