Genetic Analysis of Twins
Introduction
Analysis of genetics is significant in the field of medicine, which helps in determining people’s characteristics in relations to their environments. Thus, this paper analyzes the case of twin girls, whereby their genetics offer valuable information for both health and psychological exploration. That is, the unique characteristics between Barbara and Brenda allow us to differentiate and examine environmental influences on genetics.
Q1: Do their features represent genotypes or phenotypes?
Phenotypes are physical characteristics, and are determined by observation. Hence, their brown, wavy hair, freckles, hazel eyes and thin lips represent their phenotypes. On the other hand, genotypes are a set of genes in the DNA that is responsible for the presence of a particular trait in a person. Thus, their behavioral differences can be classified as the genotypes, which are made of “alleles” as a form of gene that is responsible for producing various effects in people. Specifically, Brenda’s outgoing personality and Barbara’s shyness are the two features of genotypes in the twins.
Q2: Which characteristics are of homozygous and which are heterozygous genotypes?
Homozygous describes an organism (or a person) with two identical versions of one gene, whilst heterozygous describes a gene pair with two different versions. In simpler terms, a homozygous person has two yet identical alleles, while a heterozygous person has two different alleles. Therefore, in this case, both Brenda and Barbara share physical features from their mom and dad, which is either the hazel eyes, brown and wavy hair, thus making them homozygous. At the same time, their completely different personalities describe their heterozygous nature, whereby Brenda takes after her extroverted dad as Barbara takes after her shy mom.
Q3: Which characteristics are due to single gene inheritance, and which are polygenic inheritance?
Single gene inheritance transpires when one pair of gene consists of two alleles. For instance, when a person’s one allele inherits from the mother and the other allele comes from the mother. Similarly, the twins’ obvious single gene inheritance is their “nice” and “friendly” traits for Barbara and Brenda respectively. Although their parents’ physical features are not mentioned, it is possible the twins inherited some form of traits from either parent. Similarly, their polygenic inheritance is evidenced by their wide variations in behaviors such as Brenda being talkative while Barbara being shy.
Q4: What types of careers are they likely to pursue. What type of gene-environment relations explains career selection?
Barbara can find herself in careers in the science areas such as biochemist, engineer, data science, etc. On the other hand, Brenda, being an outgoing personality, she might find herself thriving as a journalist, a sales representative, registered nurses, etc. The type of gene-environment relation (or rGE) in this particular case is the Active rGE, which usually takes place whenever a person possesses heritable characteristics with the inclinations to prefer certain environmental exposures and comfortability.
Conclusion
As seen in the different analyses, the genetics of both Brenda and Barbara are significant in letting us understand the extent of their diverse traits despite being identical twins. That is, without the phenotype, genotypes, and gene environment relations, it would be difficult to explain the poison ivy case. Better yet, examining the case of twins in genetic analysis has the advantage of helping us detect environmental influences on genetics.
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