Look at the figure below. Which number does it resemble most, a nine or a seven? Some people say nine, others say seven.
Scientists have discovered that how you perceive this figure is determined by a gene. People who see a nine have one form or allele of this gene, people who see a seven have a different allele.
It seems that people who carry the nine gene are most often found in southern Europe, particularly Spain (though at least one individual carrying the nine gene has been reported as far north as Utrecht). In contrast, people with the seven gene tend to live in northern Europe, particularly Britain.
Presence of one form of the gene or the other is also linked with certain personality traits. People carrying the nine gene tend to have a very liberal or tolerant attitude towards the use of drugs, arguing that they don’t really matter or affect performance. People with the seven gene are known to take a hard-line stance in public on drugs, and are vehement in denying that they personally ever have or would take these substances.
People with these traits generally are homozygous for this gene, that is, they contain either two copies of the nine allele or two copies of the seven allele. Individuals homozygous for one allele generally don’t get along well with people homozygous for the other form. Fortunately, though, some people are heterozygous, that is, they contain one copy of each allele. Since neither allele is dominant, heterozygous individuals tend to exhibit traits somewhat between those of homozygous individuals. That is, they do not take an extreme nine view or an extreme seven view, but tend to be more moderate in their beliefs.
Unfortunately, the population of heterozygotes is thought to be dwindling. Since those homozygous for nine do not get along with those homozygous for seven, it’s almost inconceivable that they would intermarry, and produce children, some of whom would be heterozygotes. Thus heterozygotes result only from the intermarriage of each other. Simple Mendelian laws, of course, indicate that only half the children of such marriages would themselves be heterozygous. So the population of heterozygotes is dwindling.
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Scientists have discovered that how you perceive this figure is determined by a gene. People who see a nine have one form or allele of this gene, people who see a seven have a different allele.
It seems that people who carry the nine gene are most often found in southern Europe, particularly Spain (though at least one individual carrying the nine gene has been reported as far north as Utrecht). In contrast, people with the seven gene tend to live in northern Europe, particularly Britain.
Presence of one form of the gene or the other is also linked with certain personality traits. People carrying the nine gene tend to have a very liberal or tolerant attitude towards the use of drugs, arguing that they don’t really matter or affect performance. People with the seven gene are known to take a hard-line stance in public on drugs, and are vehement in denying that they personally ever have or would take these substances.
People with these traits generally are homozygous for this gene, that is, they contain either two copies of the nine allele or two copies of the seven allele. Individuals homozygous for one allele generally don’t get along well with people homozygous for the other form. Fortunately, though, some people are heterozygous, that is, they contain one copy of each allele. Since neither allele is dominant, heterozygous individuals tend to exhibit traits somewhat between those of homozygous individuals. That is, they do not take an extreme nine view or an extreme seven view, but tend to be more moderate in their beliefs.
Unfortunately, the population of heterozygotes is thought to be dwindling. Since those homozygous for nine do not get along with those homozygous for seven, it’s almost inconceivable that they would intermarry, and produce children, some of whom would be heterozygotes. Thus heterozygotes result only from the intermarriage of each other. Simple Mendelian laws, of course, indicate that only half the children of such marriages would themselves be heterozygous. So the population of heterozygotes is dwindling.