Evolving our Genetic Ideas
Evolution was a recognized theory long before heredity was properly understood, however, Darwin has allowed us to understand human evolution to a far greater extent than he would have ever imagined. Genetics can be expressed in many different ways. The more often a specific phenotype is observed within the population may relate to how favourable that phenotype is for survival. This is because of relative frequency and lethality. Relative frequency is the number of times a specific allele is present within a gene pool compared to other alleles for the same trait within the gene pool.(textbook) Lethality is a little more complex. Lethal alleles cause an embryo to miscarry when they are present. Recessive lethal alleles …show more content…
In some cases this is true, however, there are also pleiotropic genes. These genes control more than one trait. Most of the time, the traits that are all controlled by the same gene seem to be completely unrelated, but they have one commonality that allows them to be grouped together. When a pleiotropic gene is mutated it affects all of the traits that the gene controls. An example of this is marfan's syndrome. This genetic disease causes people to be abnormally tall, have very long and thin fingers and toes, have an increased chance of lens dislocation of the eye, and be prone to aortic ruptures. As stated earlier, all of these traits are caused by a single gene mutation, causing the body to produce very few fibrils. (Khan’s Academy, n.d.)
What is Dominant? Genes typically present themselves as dominant or recessive. If a dominant allele is present, it will be expressed. If there is a lack of dominance, a less common recessive allele will be expressed. However, dominance can express itself in different ways. Co-dominance is displayed when there are two dominant alleles that are both expressed. Incomplete dominance is shown when two phenotypes blend together to create an entirely new phenotype. (Miller & Levine,
Evolution was a recognized theory long before heredity was properly understood, however, Darwin has allowed us to understand human evolution to a far greater extent than he would have ever imagined. Genetics can be expressed in many different ways. The more often a specific phenotype is observed within the population may relate to how favourable that phenotype is for survival. This is because of relative frequency and lethality. Relative frequency is the number of times a specific allele is present within a gene pool compared to other alleles for the same trait within the gene pool.(textbook) Lethality is a little more complex. Lethal alleles cause an embryo to miscarry when they are present. Recessive lethal alleles …show more content…
In some cases this is true, however, there are also pleiotropic genes. These genes control more than one trait. Most of the time, the traits that are all controlled by the same gene seem to be completely unrelated, but they have one commonality that allows them to be grouped together. When a pleiotropic gene is mutated it affects all of the traits that the gene controls. An example of this is marfan's syndrome. This genetic disease causes people to be abnormally tall, have very long and thin fingers and toes, have an increased chance of lens dislocation of the eye, and be prone to aortic ruptures. As stated earlier, all of these traits are caused by a single gene mutation, causing the body to produce very few fibrils. (Khan’s Academy, n.d.)
What is Dominant? Genes typically present themselves as dominant or recessive. If a dominant allele is present, it will be expressed. If there is a lack of dominance, a less common recessive allele will be expressed. However, dominance can express itself in different ways. Co-dominance is displayed when there are two dominant alleles that are both expressed. Incomplete dominance is shown when two phenotypes blend together to create an entirely new phenotype. (Miller & Levine,