Sunday, June 28, 2009
Tuesday, November 14, 2006
Why Study Genetic Influences on Human
Behavioral Traits?
A simple answer to the question of why to study genetic influences on human behavior is, for a better understanding of
how things work i.e. how the behavior of a man changes ? Is there any responsible gene for such changes? Are there effects of genes for particular trait more pronounced in men or women? Are there interactions between genes and the environment? For example, it has been for a long time that stressful life events lead to depression in some people but not others. There is now evidence of an interaction. Individuals who carry a specific genetic variant are more susceptible to depression when exposed to stressful life events than individuals who do not carry the genetic variant. Are there gene-environment correlation? To study all those things the genetic influence on behavior of human should be studied.
Is There Any Importance Of This Research for Society?
Yes, due to this research many of the mysteries will be revealed.
Now a days the most popular questions which cycle through society are: Are behaviors inbred; written indelibly in our genes as immutable biological imperatives or is the environment more important in shaping our thoughts and actions? To satisfy such questions the research is useful.
There are many importances to the society such as:
1) To diagnose the traits such as criminality or homosexuality
A} Criminality - Now, the Human Genome Project is completed successfully and hence we have known the functions of the most of the genes. According to the conference on ‘Genetic Factors in Crime’ organized by National Institute of Health in 1992, the genetic factors are responsible for violence. Hence by replacing those genes or by controlling the expression of those genes we can decrease the level of criminal thoughts in individual’s mind.
A study has shown, in USA, increased level of testosterone hormone, generally, causes to criminal thoughts. Hence by controlling that gene expression we can reduce the criminal thoughts from the society.
B} Homosexuality – In 1993, Dean Hamer found a section of X chromosome which leads to homosexuality. He named the region Xq28 and declared it as the first concrete evidence that ‘Gay gene’ really do exist. So by controlling these genes for their expression, we can reduce the percentage of such an abnormal behavior in the society.
There are many more applications of this research for society but they are now under study and research. These mentioned two examples are widely & continuously studied for the gene/behavior relationship.
Some Other Examples Showing gene/behavior
Relationship
1) Religiousness –
Religious belief is determined by a person’s genetic make-up according to a study by leading scientist. Dr. Dean Hamer, the director of the Gene Structure & Regulation Unit at the National Cancer Institute in America, found the gene named as ‘VMAT2’. After comparing samples, this American molecular geneticist concluded that VMAT2 leads to religious belief in individuals mind. Studies on twins showed that those with this gene, a vesicular monoamine transporter that regulates the flow of mood-altering chemicals in the brain, were more likely to develop a spiritual belief.
2) Intelligence –
A study published in 1999 claimed that over expression of a particular gene lead to enhanced learning capacity. Then later the gene is named as ‘The learning gene’ or ‘smart gene’. But the learning enhancements observed in this study were short-term, lasting only a few hours to a few days.
3) Kallman syndrome –
A human syndrome provides an example of how subtle and indirect relationship between genes & social behavior can be.
Kallman syndrome, hypogonadotropic hypogonadism, afflicts men with a striking behavioral change: absence of libido as part of a disinterest in the opposite sex. Causation of X-linked Kallman syndrome is now understood in light of the surprising findings that neurons producing gonado-tropin-releasing hormone (GnRH) are
Not born as expected near brain ventricular surfaces, but instead are born in the olfactory epithelium. That is, they must migrate from the nose to the brain. In fact, X-linked Kallman syndrome caused by genetic damage at Xp-22.3 has been correlated with a failure of migration of GnRH neurons – They were dammed up in the olfactory apparatus and never reached the brain. In turn, this neuron migration disorder is rationalized by the fact that damage at Xp-22.3 disrupts a specific gene whose damage causes X-linked Kallman syndrome, and this gene codes for a cell surface protein present during migration of GnRH neurons into the brain.
How Do Genes Influence Behavior?
Behavior may be defined as the process of responding to some form of energy in the environment by the biological activity within the body generally useful to life. The energy or less exactly the object from which it is derived, is known as the ‘stimulus’, while the resulting activity is called the ‘response’. If the response is harmful or useless to society members, the behavior is supposed as ‘bad behavior’ and when the response leads to happiness or helping to someone, the behavior supposed as ‘good behavior’. This is fact.
“A Harvard biologist argues that parents and teachers do not teach children the rules of correct behavior from scratch, but only give shape to innate concepts of morality.”
A] Physiological Basis of Human Behavior :
1) Cortical activity in social Behavior –
We may regard those parts of the central nervous system which lie below the cortex as the centers of the primitive reflex activities characteristic of all animals endowed with a nervous system. Such reflexes include respiration, digestive and simple movements of the appendages in defense and escape. Such reflexes are generally innate and foe their functioning the spinal cord, medulla, cerebellum, midbrain and thalamus suffice. The human being, however, has added to this simple repertory a formidable array of activities whose arcs involve and necessitate a cerebral cortex. He has acquired language, spoken and written, and other habits of skill. He has learned the use of tools, and has acquired sagacity through storing up the effects of past experiences. He has, in short, through the adoptive capacities of the cortex, attend the levels of intelligence and the power of inhibition and control which are requisite for civilized society.
The chief contributions of the cortex to social behavior may be summarized as fallows:
1) It underlies all solutions of human problems which are also social problems and makes possible their preservation in language, customs, institutions and inventions.
2) It enables each new generation to profit by the experience of others in learning this transmitted lore of civilization.
3) It establishes habits of response in the individual for social as well as individual ends, inhibiting and modifying primitive self –seeking reflexes in to activities which adjust the individual to the social as well as the non-social environment. Socializes behavior is thus the supreme achievement of the cortex.
B] Actual Mechanism By Which Genes Control Behavior—
“The human body is nothing but the set of biochemical reactions.” This is the fact we have to agree with this. These different types of biochemical reactions are regulated by different substances i.e. proteins, Hormone, enzymes. Among these three substances mostly hormones regulates the behavior. These hormones are nothing but the processed proteins .The Proteins are synthesized by the fundamental mechanism of body i.e. gene expression. Gene Expression is the process by which the proteins are synthesized with the help of coded information on the gene. There are some steps in gene expression:
1) Transcription - mRNA Synthesis
2) Translation - Protein synthesis
3) Protein processing - conversion of raw protein in specific form which is required i.e. hormone or enzyme or protein itself.
Reference:
1] Animal Behavior – Reena Mathur {edition :
Page no. : }
2] The National Academy of Sciences.
URL- http://www.pnas.org/hormones,genes.html
3] http://www.rockfeller.edu/research/abstract.php
4]
http://www.ornl.gov/sci/techresources
5] Department of Sociology, Brock University,
St. Catharines, Canada .
URL –http://www.spartan.ac.brocku.ca/..../1924/19240 2
Behavioral Traits?
A simple answer to the question of why to study genetic influences on human behavior is, for a better understanding of
how things work i.e. how the behavior of a man changes ? Is there any responsible gene for such changes? Are there effects of genes for particular trait more pronounced in men or women? Are there interactions between genes and the environment? For example, it has been for a long time that stressful life events lead to depression in some people but not others. There is now evidence of an interaction. Individuals who carry a specific genetic variant are more susceptible to depression when exposed to stressful life events than individuals who do not carry the genetic variant. Are there gene-environment correlation? To study all those things the genetic influence on behavior of human should be studied.
Is There Any Importance Of This Research for Society?
Yes, due to this research many of the mysteries will be revealed.
Now a days the most popular questions which cycle through society are: Are behaviors inbred; written indelibly in our genes as immutable biological imperatives or is the environment more important in shaping our thoughts and actions? To satisfy such questions the research is useful.
There are many importances to the society such as:
1) To diagnose the traits such as criminality or homosexuality
A} Criminality - Now, the Human Genome Project is completed successfully and hence we have known the functions of the most of the genes. According to the conference on ‘Genetic Factors in Crime’ organized by National Institute of Health in 1992, the genetic factors are responsible for violence. Hence by replacing those genes or by controlling the expression of those genes we can decrease the level of criminal thoughts in individual’s mind.
A study has shown, in USA, increased level of testosterone hormone, generally, causes to criminal thoughts. Hence by controlling that gene expression we can reduce the criminal thoughts from the society.
B} Homosexuality – In 1993, Dean Hamer found a section of X chromosome which leads to homosexuality. He named the region Xq28 and declared it as the first concrete evidence that ‘Gay gene’ really do exist. So by controlling these genes for their expression, we can reduce the percentage of such an abnormal behavior in the society.
There are many more applications of this research for society but they are now under study and research. These mentioned two examples are widely & continuously studied for the gene/behavior relationship.
Some Other Examples Showing gene/behavior
Relationship
1) Religiousness –
Religious belief is determined by a person’s genetic make-up according to a study by leading scientist. Dr. Dean Hamer, the director of the Gene Structure & Regulation Unit at the National Cancer Institute in America, found the gene named as ‘VMAT2’. After comparing samples, this American molecular geneticist concluded that VMAT2 leads to religious belief in individuals mind. Studies on twins showed that those with this gene, a vesicular monoamine transporter that regulates the flow of mood-altering chemicals in the brain, were more likely to develop a spiritual belief.
2) Intelligence –
A study published in 1999 claimed that over expression of a particular gene lead to enhanced learning capacity. Then later the gene is named as ‘The learning gene’ or ‘smart gene’. But the learning enhancements observed in this study were short-term, lasting only a few hours to a few days.
3) Kallman syndrome –
A human syndrome provides an example of how subtle and indirect relationship between genes & social behavior can be.
Kallman syndrome, hypogonadotropic hypogonadism, afflicts men with a striking behavioral change: absence of libido as part of a disinterest in the opposite sex. Causation of X-linked Kallman syndrome is now understood in light of the surprising findings that neurons producing gonado-tropin-releasing hormone (GnRH) are
Not born as expected near brain ventricular surfaces, but instead are born in the olfactory epithelium. That is, they must migrate from the nose to the brain. In fact, X-linked Kallman syndrome caused by genetic damage at Xp-22.3 has been correlated with a failure of migration of GnRH neurons – They were dammed up in the olfactory apparatus and never reached the brain. In turn, this neuron migration disorder is rationalized by the fact that damage at Xp-22.3 disrupts a specific gene whose damage causes X-linked Kallman syndrome, and this gene codes for a cell surface protein present during migration of GnRH neurons into the brain.
How Do Genes Influence Behavior?
Behavior may be defined as the process of responding to some form of energy in the environment by the biological activity within the body generally useful to life. The energy or less exactly the object from which it is derived, is known as the ‘stimulus’, while the resulting activity is called the ‘response’. If the response is harmful or useless to society members, the behavior is supposed as ‘bad behavior’ and when the response leads to happiness or helping to someone, the behavior supposed as ‘good behavior’. This is fact.
“A Harvard biologist argues that parents and teachers do not teach children the rules of correct behavior from scratch, but only give shape to innate concepts of morality.”
A] Physiological Basis of Human Behavior :
1) Cortical activity in social Behavior –
We may regard those parts of the central nervous system which lie below the cortex as the centers of the primitive reflex activities characteristic of all animals endowed with a nervous system. Such reflexes include respiration, digestive and simple movements of the appendages in defense and escape. Such reflexes are generally innate and foe their functioning the spinal cord, medulla, cerebellum, midbrain and thalamus suffice. The human being, however, has added to this simple repertory a formidable array of activities whose arcs involve and necessitate a cerebral cortex. He has acquired language, spoken and written, and other habits of skill. He has learned the use of tools, and has acquired sagacity through storing up the effects of past experiences. He has, in short, through the adoptive capacities of the cortex, attend the levels of intelligence and the power of inhibition and control which are requisite for civilized society.
The chief contributions of the cortex to social behavior may be summarized as fallows:
1) It underlies all solutions of human problems which are also social problems and makes possible their preservation in language, customs, institutions and inventions.
2) It enables each new generation to profit by the experience of others in learning this transmitted lore of civilization.
3) It establishes habits of response in the individual for social as well as individual ends, inhibiting and modifying primitive self –seeking reflexes in to activities which adjust the individual to the social as well as the non-social environment. Socializes behavior is thus the supreme achievement of the cortex.
B] Actual Mechanism By Which Genes Control Behavior—
“The human body is nothing but the set of biochemical reactions.” This is the fact we have to agree with this. These different types of biochemical reactions are regulated by different substances i.e. proteins, Hormone, enzymes. Among these three substances mostly hormones regulates the behavior. These hormones are nothing but the processed proteins .The Proteins are synthesized by the fundamental mechanism of body i.e. gene expression. Gene Expression is the process by which the proteins are synthesized with the help of coded information on the gene. There are some steps in gene expression:
1) Transcription - mRNA Synthesis
2) Translation - Protein synthesis
3) Protein processing - conversion of raw protein in specific form which is required i.e. hormone or enzyme or protein itself.
Reference:
1] Animal Behavior – Reena Mathur {edition :
Page no. : }
2] The National Academy of Sciences.
URL- http://www.pnas.org/hormones,genes.html
3] http://www.rockfeller.edu/research/abstract.php
4]
http://www.ornl.gov/sci/techresources
5] Department of Sociology, Brock University,
St. Catharines, Canada .
URL –http://www.spartan.ac.brocku.ca/..../1924/19240 2
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