Heterozygous Gene For Tay Sachs Disease example essay topic

Natural selection can have its positives and negatives. These articles all consist of a general idea that species with heterozygous genes have the advantage over others of being immune or having a special defense against certain diseases. The disadvantage with that being that though they lucked out, their next of kin may get a bad roll of the genetic dice and have some sort of horrible disease. Due to culture and morals sometimes certain cultures continue to breed within their own and not spread these positive immunities. For instance, the Jewish culture is taught to keep their populace entirely pure.

The trouble with that is it's causing a problem in the Eastern European group of Jews. Scientist have studied that the Tay-Sachs disease is more common in Eastern European Jews than in any other race. Also that in their ancestors a common cause of death was Tuberculosis (TB). TB being easily obtained when in close quarters, as with any other disease, was common due to the poor living conditions that Eastern Europeans were exposed to. People who survived the disease mostly had the heterozygous gene for Tay-Sachs disease making them chemically have better defense against the TB disease. In result Natural selection chose the heterozygous Jews over the homozygous.

However this now causes conflict when Heterozygous with the gene have a 1 and 4 chance of giving their child the Tay-Sachs disease causing major devastation in ones family. In other Ethnicities, African American's have a high rate of Sickle Cell Anemia. Sickle Cell is an unfortunate disease that when obtaining both homozygous genes, results in death. All African American ancestors originated from Africa where malaria is a large obstacle. With poor health conditions and lack of medicines one dies from it. However in later generations people who had the heterozygous genes were more likely to be immune of the disease, or have a better defense.

Making heterozygous African Americans outlive the homozygous ones. However when slave trade began taking place these heterozygous descendants were coming to America in poor living conditions. Close quarters, little water, and heat conditions gave the heterozygous sickle cell carriers a disadvantage. It is said that natural selection has taken place and has made it so that people in those living conditions that had a certain liver defect, of being able to hold more salt, were more likely to survive those who could not hold as much salt. Making having a higher capacity for holding salt in the liver the ideal trait. Considering the diet of the typical American today it is not practical to have a liver that retains salt.

Making African Americans with that trait more likely to have high blood pressure resulting in heart attacks and other high blood pressure diseases. Once again natural selection is taking place and reversing its coarse with the once important salt retaining liver gene defect. One more instance of having an accidental ideal gene is in Asians. Some lack the enzyme called aldehyde hydrogenate (A LDH 2). The positives of this are; when during alcohol consumption the average person can continue to drink alcohol and not get sick because this enzyme breaks it down.

In lacking this enzyme the body instantly rejects the alcohol making consuming it an unpleasant experience that mostly likely wont happen again. Making alcoholism highly unlikely in the Asian population. Studies in monkeys show that when taken from their mother at birth and being brought up by peers instead monkeys are more likely to be alcoholics. Where as monkeys brought up by their mothers are shown self-restraint not making them as impulsive and aggressive when it comes to social life and making good decisions. This I believe is the main factor in causing alcoholism. Though genes may have a bit to do with it, I don't believe it is possible that one is born with an "alcohol disease gene".

However alcohol may be a factor in a bigger disease in hyper and hypo manic people but to say it is its own disease I believe is a bit of a stretch. As I have shown three instances in which it is ideal to have heterozygous genes there are millions of other variations out there that have the same effect. Basically it shows where natural selection is headed in the spectrum of genes. For now its all a game of chance but, I predict that far beyond you " re or mine's time, with enough mixing, we will all become a melting pot and all have the genes of the heterozygous immunities making these deadly disease dies off.

But it also brings up the conflict that there may be a rise in homozygous diseases. But until then it is quite the struggle between disease and natural selection in a survival of the fitness battle.