by Boris Sagredo

Course: PLSC 631 INTERMEDIATE GENETICS. Professor: Phillip McClean

Department of Plant Sciences North Dakota State University. Fargo, North Dakota


Genetic is changing our world

Genetic has provided some powerful knowledge that is changing humanity's view of itself and its relation to the rest of the universe. This has brought changes of our current philosophies and religions. For instance, the catholic church has accepted the evolution theory (1). Genetic, cytogenetic and molecular studies show that we are related to every living thing on the planet, including plants, fungi and bacterium (6)

An important area in which current genetic knowledge is causing revolution is anthropological science (14). DNA of the human specie carries more or less the same set of DNA, but small variations in the DNA contributes to human variations. So, genomic variations of the human specie are being studied, through analysis of DNA from populations, families, and individuals worldwide. Ancient DNA is used for to do studies of evolution.

Many genetic diseases may be detected early

Medicine is a very important area in which genetics is a powerful tool. Indeed, a large proportion of human health has a genetic basis. Inherited genetic diseases are caused by abnormal forms of a single or a group of genes that are passed on from one generation to the next. Some single genes responsible for inherited genetic diseases, such as the ones responsible for familial Alzheimer's disease, familial breast cancer and cystic fibrosis (6) are being isolated and characterized at molecular level. More complex human hereditary disorders, those which are caused by the interaction of several genes, also interacting with the environment, such as heart diseases, hypertension, diabetes, various forms of cancer and infections, are also being investigated using a molecular approach (13).

HGP and HGDP a great international effort

Many countries are developing a collaborative effort to obtain the complete human genetic sequence and measure the diversity of the human specie (4, 10). The Human Genome Project (HGP) was formally initiated in 1990 and has, as its specific goal, the identification of every human gene and the sequencing of the entire genome. Completion of the HGP within the projected 15 years will provide a source book of biology and medicine. The Human Genome Diversity Project (HGDP) is an international scientific endeavor that complements the HGP. Its objective is to help us understand the fundamental unity of the humankind, human biological history, population movements and susceptibility or resistance to various human diseases.

What is genetic screening?

Realization of these great projects and others like them, requires the collecting, sequencing and comparison of many DNA genomes from different individuals and populations. In other words, it requires a massive and exhaustive genetic screening of individuals and populations.

Some institution such as the U.S. Congress Office of Technology Assessment (OTA) differentiates genetic testing from genetic screening. The first is defined as "the use of specific assays to determine the genetic status of individual already suspected to be at risk for a particular inherited condition," whereas genetic screening is using the same probe or assay, but distinguished from genetic testing by analyzing a target population. However, the most of the reports are using testing and screening interchangeably. The National Academy of Sciences (NAS) defines genetic screening as the systematic search of population for persons with latent, early, or asymptomatic disease (12). Also, in agreement with the HDP, genetic screening searches for disabling genes that, for instance, may confer resistance to specific diseases (10). Another purpose of genetic screening is to determine polymorphism that can be used as a simple genetic characterization of a population.

For medical studies, genetic screening is normally done to check for certain genes that potentially produce damaging changes in the individuals. So early detection may help to avoid its consequence. In this sense, genetic probes are useful for both prenatal diagnosis and newborn screening for detect rare metabolic diseases such as phenylketonuria (PKU), a disease which causes mental retardation and can be prevented by following a special diet, sickle cell anemia and Ashkenazic Jews for Tay-Sach disease. Screening is also useful to identify individuals that are carriers of a chromosome abnormality or gene that may cause problems for either the offspring or the person screened. During the last years probes for cystic fibrosis, Duchenne muscular dystrophy, hemophilia, Huntington'disease, neurofibromatosis and brain cancer have been developed (6, 9).

Associations between a gene and a disease can often be established by linkage studies. Using polymorphic markers which can be found in the population with a relatively high frequency, relatives (e.g., siblings) affected by a disease are identified. Then, if during this study, one form of one marker (or of a close linked marker) is found significantly more often than expected by chance, this marker is said to be close (or "linked") to the disease-related gene. However, some aberrant genes, such as the one for phenylketonuria (PKU) was inferred from the discovery that metabolites of phenylalanine, an amino acid, was increased in people with PKU. Following this discovery, the activity of the enzyme that catalyzed the conversion of phenylalanine to tyrosine was found to be absent or decreased in patients with PKU. Recently, with the advent of recombinant DNA technology the gene catalyzing this conversion was localized to chromosome 12 (9).

The application and scope of genetic markers is limited to studying the intrinsic features of genetic diseases, such as heterogeneity and incomplete penetrance, which reduce, respectively, the clinical sensitivity and positive predictive value of a genetic test (9).

Social dilemmas of genetic screening

The use of a genetic marker to predict early genetic disorders can be beneficial to the society, so we may prevent symptom development with early medical assistance. But, for instance, in many cases, if a genetic disease is detected in a fetus, the fetus is aborted. Also, there are cases of people that carry DNA mutations associated with a genetic disease, that are being discriminated by health insurers and employer (8). So, the genetic screening is bringing new social, legal and ethical dilemmas.

ELSI (Ethical Legal and Social Issue) working group (5), which is a special committee of HUGO (Human Genome Organization) discusses the social consequences of HGP. At its first meeting, in 1989, they identified topics that required special attention. These were fair use of genetic test information in areas such as insurance, employment, criminal justice, education, adoption and in military aspects; impact of genetic information on individuals; personal privacy and confidentiality of genetic information; the impact that the dramatic increase in human genetic information will have on genetic counseling and the delivery of genetic services; influence of genetic information and new technologies on reproductive decisions; issues raised by the introduction of new genetic information and technologies into mainstream medical practice; historical analysis of the use and misuse of genetic information and technologies; issues raised regarding the commercialization of researching results and conceptual and philosophical topics, related to human genetics.

Many leading countries in genetic research, such as USA, England, Japan, France, have extensively debate the ethical, legal and social aspects of genetic screening. Consequently, each country has its own committee that is working to identify and define issues and develop policy options to address them according to its own social-political situation.

Unites States citizens want to avoid genetic discrimination by health insurers and employers

In the United States, the most important public debate is related to possible genetic discrimination and health insurance . It is based on the fact that in the past, genetic information has been used by insurers to discriminate against people. In the early 1970s, some insurance companies denied coverage and charged higher rates to African Americans who carried the gene for sickle anemia. Nowadays, some cases of genetic discrimination against people who are healthy but have a gene that predisposes them or their children to diseases later in life such as Huntington's disease, have been reported. In a recent survey, 22% of the people with a known genetic condition in the family, indicated that health insurance coverage has been denied to them due to their genetic status (8).

Hudson et al, in "Genetic Discrimination and Health Insurance: an Urgent Need for Reform" (8) recommended and defined some actions and concepts to federal policy markers, to protect society from genetic discrimination. This recommendation is that insurance providers should be either prohibited from using genetic information, or an individual's request for genetic services, to deny or limit any coverage or establish eligibility, continuation, enrollment, or contribution requirements. Moreover, providers should be prohibited from establishing differential rates or premium payments based on genetic information or an individual' request for genetic services and, they should be prohibited from requesting or requiring collection or disclosure of genetic information. Also, insurance providers and the holders of genetic information should be prohibited from releasing genetic information without prior written authorization of the individual. They defined genetic information as information about genes, genes' products, or inherited characteristics they may derive from the individual or family member and insurance providers were defined as an insurance company, employer, or any other entity providing a plan of health insurance or health benefits including group and individual health plans either fully insured or self-funded.

Those who agree that genetic screening positively affects the medical care of individual patients and see a need to ensure the freedom of patients, last year presented a bill to the Committee on Labor and Human Resources (15). This bills is titled "The genetic confidentiality and nondiscrimination act of 1996". It proposes the definition of the circumstances under which genetic information may be created, stored, analyzed, or disclosed, and defines the rights of individual and persons in relation to genetic information; responsibilities of others in respect to genetic information; protection of individuals from genetic discrimination; establishment of uniform rules that protects individual genetic privacy and allows the advancement of genetic research and establishment of effective mechanisms to enforce the rights and responsibilities.

Health insurance providers state, said that the impact of genetic information on insurance rates and availability is in some cases exaggerated. And that restrictions as the ones mentioned above, which forbid health insurance companies from using information to deny coverage to potential clients, are not appropriate for the viability and profitability of insurance companies. Moreover, genetic information is often costly to obtain, and the benefits of reducing claim cost may not be commensurate with the cost of obtaining the information on the numerous applicants screened every day by insurance companies (2, 3).

Some people think that genetic screening may be used to identify good genome (3), so, those with it will insist on better rates by the insurers. Unlike negative discrimination, an eventual positive discrimination could have a positive effect on genetic research and preventive medicine by encouraging people to participate in genetic tests. But it would raise exactly the same social and ethical issues because insurers, under competitive pressure, would have to lower rates for individuals with a low genetic risk and consequently increase rates for those with a high genetic risk. So, insurers responding to new market demand, will design new products with limited coverage and lower rates, which will be the preferred choice of customers who know they have a genetically low risk, whereas people who know they have a higher risk will incline towards more extensive coverage with higher rates.

In the last months, the US Senate approved, unanimously, a health reform bill that explicitly bars insurers from using genetic information to deny coverage to applicants. The main goal of the Senate bill, whose authors were Senators Nancy Kassebaum and Edward Kennedy, is to prevent people from losing health insurance when they change or leave jobs (7).

Humanity must be well prepared for the coming of new genetic knowledge

Naturally, each one of the topics exposed above such as genetic discrimination by insurers and employers and all moral, legal and ethical dilemmas that brings genetic screening and new knowledge from genetic, has a distinct importance in each country, according to its culture, political and social organization and its developmental state. So, for example, some countries as Japan and Australasia had reported high acceptance of genetic screening and gene therapy (11). Other countries in the Scandinavian region, have a different health insurance system than U.S., and consequently dilemmas such as genetic discrimination have a distinct sense (16).

In response to many of these dilemmas, recently the International Bioethics Committee of UNESCO published a draft called "Declaration on the Human Genome and its Protection in relation to Human Dignity and Human Rights." (17) It contains twenty-one articles that ensure the rights of people from new genetical activities. So, it declared that human genome is a fundamental component of the common heritage of humanity and needs to be protected in order to safeguard the integrity of the human specie, as a value in itself, and the dignity and right of each of its members. The human genome, which by its nature evolves and is subject to mutations, contains potentialities that are expressed differently according to the environment, education, living conditions and state of health of each family and each individual. Each human being possesses a specific genetic identity. An individual's personality cannot be reduced to his or her genetic characteristics. Every individual has the right to be respected regardless of this characteristics. So, the document articles define specific rights and responsibilities for everyone who participates in DNA human research to help to ensure human right and freedom and to allowed the DNA human genome studies to be successful. Also, there are articles that attempt to promote and rule the international cooperations.


At now, our philosophies and religions are undergoes profundus changes from new genetic knowledge. Indeed, the humanity's view of itself and its relation to the rest of universe is changing. Now we know that every living thing, included the man, on the planet are related.

Due the benefits enormous that may bring the knowledge genetic of the human genome, many countries are developing a collaborative effort to obtain the complete human genetic sequence and measure the diversity of a human specie. These benefits are being seen principally in the medical area. In fact, there are many diseases, such as Alzheimer'disease, familial breast cancer and cystic fibrosis between other, that can be detect early using genetic probes. A early detection of genetic disease may prevent symptom development with a early medical assistance. Both activities, the application of DNA probes to detect early genetic diseases and researching in human genome require a continuous checking of genomes from different individual or populations. The last we can to define as genetic screening, even although there are different definitions.

Together with the benefits for medical and research proposes, genetic screening are bringing a series of ethical and social dilemmas. Indeed, the early genetic information from a fetus clearly can influence a decision of abort, this today is broadly discussed from different religions. Also, some people have afraid that genetic screening will be used for discrimination against by health insurers and employers.

There many initiatives, the most conduced for scientists, sociological experts and lawyers, specially from those countries that are leading genetic researching, that appoints to identify and prevent the possible problems from genetic screening. Always the goal is ensure the benefits of genetic screening and prevent its possible problems. Some countries, such as U.S., already had at senate level approved a bill that prevent genetic discrimination against by health insurers.

In each country in according its culture, political and social organization and its developmental state, the moral and ethical dilemmas that bring the genetic screening are different. Even although, the International Bioethics Committee of UNESCO published a document that attempt ensure and guide, the human right and freedom, and genetic researching, respectively.

In my opinion, the great task of Institutions such as ELSI, the International Bioethics Committee of UNESCO that are guiding the public debate about the ethical, legal and social dilemmas from the genetic screening is very important. Indeed, the genetic screening had brought already benefits notable in medical assistance, but there are also report about misuse of genetic information by health insurers (8). Then, we need to ensure good social benefits from genetic testing and prevent its misuse, it only is possible with a serious debate in all countries to identify which are the principal problems and dilemmas generated for genetic screening applications and attempts solved it with adequate laws.

Therefore, any person or institution that feels that the future of our humanity will be compromised must also participate in these debates.

Certainly, our human society is very complex, then is so difficult to estimate with accuracy which are the possible dilemmas and impact that may bring the massive application of news genetic knowledge in medical proposes or another area. Of course, the possibility of benefits enormous in medicine and other fields are sufficiently to justify the great effort that are doing scientist and countries to obtain the complete human genetic, and development DNA probes to detect different kind of genes associated to inheritaded diseases. Other interesting goal is to identify genes of disease resistance from human population so, in the future, eventually may used for gene therapy.

However, we shall not forget that the human behavior is complex and not so far that sixty years, the world was involved in a racist war. Indeed, recently some french scientists claimed for prevent possible racist impetus (18). Also there is a highly publicized book of Richard Hernstein and Charles Murray's "The Bell Curve", which claimed that IQ is largely genetically determined and that the difference in IQ between ethnic groups are substantially explained by genetic factor. However, the ELSI Working Group responded to "The Bell Curve" (19), explained which were the methodological and concept errors that these authors did in their genetic analysis, and said that the predictability of trait such as IQ is very complex, because probably in its expression participate many genes and is highly influenced by environmental factors. Moreover the eugenism was qualified as dangerous.

Anyway I quite agree with scientists in affronting any possible problem by misunderstanding of genetic knowledged and possible negative effects of genetic screening to prevent them and ensure the great benefits for the humankind.


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