Topic 4 DQ 1
|Advantages and disadvantages in using twins to analyze genetic heritability|
Discuss some of the advantages and disadvantages in using twins to analyze genetic heritability. Why might it be useful for future twin studies to separate out monozygotic (identical) from dizygotic (fraternal) twins?
PSY 255 Personality Psychology Topic 4 DQ 1
The advantages in using twins to analyze genetic heritability is twins are the closest model type that behavior geneticists can use for scientific experiments. It is most useful, as you probably already know, to separate out the identical twins from the fraternal twins. Why? Identical twins develop from a single fertilized egg; whereas, fraternal twins develop from separate fertilized eggs. There are no more similarities in fraternal twins than there are with the kids down the block in the same neighborhood. Advantages and disadvantages in using twins to analyze genetic heritability.
When we take a closer look at how a human is created and how our genes are developed, we get a clearer understanding how different people truly are; even when born into the same household with the same parents. Humans have different chromosomes, DNA, and genes. These genes according to David Myers believes, “You have 30,000 or so gene words” (2011), that is a lot of gene words for a person’s personality to develop from.
When we think about God, who created each one of us. “We are the clay, you are the potter; we are all the work of your hand” (Isaiah 64:8). I am overwhelmed by the realization of how much God loves us, to create us all differently. We are an original, no two people have the same fingerprint or identical DNA. You and I are masterpieces, “…I am fearfully and wonderfully made: marvelous are your works…” (Psalm 139) Advantages and disadvantages in using twins to analyze genetic heritability.
Being created unique and differently, still raises the age-old question, how much does enviroment (nurture) influence personality? Parents still do influence a child’s attitude, value, manners, faith, and politics. Suppose you take identical twins, and the parents divorce and each parent takes one child and raises them differently. According to behavior geneticists the twins could still have the same likes, dislikes, mannerisms, laugh, sense of humar, and tastes in spouses. In conclusion, genetic heritability is still a mystery.
Myers, D.G. (2011). Exploring Psychology: Eighth edition in modules. New York, NY: Worth Publishers.
Re: Topic 4 DQ 1
The advantage is you have two genetically identical people that came from the same egg (monozygotic) and are virtually a carbon copy on one and another. Analyzing the set of twins can give you duplicate results and verifying the results will not be as difficult if they are the only set of children in the family. If they have other siblings then you have two sets of results that can be verified or contested with the other sibling(s). If the heritability results match then we can see we do inherit some of our personality genes from our parents. The disadvantage is they are both raised in the same environment and one can say the environment has an influence in shaping a portion of their personality. Another advantage is the nonadditive effect for monozygotic twins. The probability of sharing exact combination of genes is greater in monozygotic twins than it is with dizygotic twins. Nonadditive effects strengthen the genetic heritability in monozygotic twins but not in dizygotic twins. One serious ethical issue I can see is separating monozygotic or dizygotic twins at birth and separating them by distance and economical tiers to validate the genetic heritability. Advantages and disadvantages in using twins to analyze genetic heritability.
Topic 4 DQ 1
The different types of twins include identical and fraternal twins. Identical twins are made when a fertilized egg is split; thus creating twins. Fraternal twins are made when two eggs are fertilized at the same time. Each set of twins are unique and different in their own ways. However, one major advantage to twins is their genetic makeup. Twin A and twin B always have the same DNA which can somewhat be looked at as variables. One twin could technically be the dependent variable and the other the dependent due. Advantages and disadvantages in using twins to analyze genetic heritability. For example, if trying to research if breast milk really is best for a baby a mother could breast feed baby A and formula feed baby B. Using the twins that have the same genetic makeup leave less margin for error in my opinion. To look at this from a personality psychological stand point let’s take the movie parent trap. Identical twin girls are separated and live two completely different life styles. If we were trying to see if the twins developed any personality traits from their other parent it would be easier because we would not have the actual parents personality shaping how they are. It would be considered an outside factor because they are not influenced every day by their superego. However, if they were to be raised in the same environment this would leave to the possibility of disadvantages of both their mother and father having an effect on their personalities Advantages and disadvantages in using twins to analyze genetic heritability. Although I believe it is unethical to purposely separate twins I do believe there can be positives to it and if done in a good way can be beneficial. For example, I have three sets of twins in my class; one set of parents is very adamant about them being together at all times; the other two could careless as long as it does not affect their behavior in a negative way. We separate twin O and twin J at meal times because we know if they are together they tend to throw food, kick their friends, and not eat. However, at nap time we have them together because they sleep better when near each other. In my opinion, if done in a manner that does not separate them fully it is best for both twins. Advantages and disadvantages in using twins to analyze genetic heritability
To introduce this week’s topic of the advantages and disadvantages faced in using twins to analyze genetic heritability, I found the following quote that Burger (2011) mentions relevant: “Eysenck maintained that the individual differences in personality he described are based on physiological differences” (p. 200-201). I feel that this could readily apply to twins. Now, in regard to the actual advantages and disadvantages, one of the most apparent advantages of using twins to analyze genetic heritability is that they share DNA. Therefore, if the testing shows that they have the same characteristics, even if they live separately, that would be evidence to show that twin studies are effective. Another advantage in using twins to analyze genetic heritability is that, according to Burger (2011), “Other methods for teasing apart genetic and environmental influences also find evidence for genetic influence, but are not as strong as in the twin-study data…The strongest and most consistent evidence in favor of genetic influence on personality comes from twin-study research” (p. 235-237). This goes to show just how efficacious data from the twin-study research is relative to other methods of gathering data. Now, a disadvantage of twin-study research is that, “researchers assume that MZ and DZ twins have equally similar environments. However, there is evidence that MZ twins may share more of their environment than DZ twins” (p. 237). This can be quite deceiving, especially when drawing conclusions from the research done on both kinds of twins. Another disadvantage of twin-study research, as Burger mentions, is, “Research suggests that personality traits aren’t passed down from parent to child in a simple, direct manner. Rather, the inherited part of personality is often the result of a combination of a complex combination of more than one gene…That is, the genetic influence of same personality traits may not be seen…” (p. 238). This can also cause deception when interpreting the results of the study. Overall, however, using twins to analyze genetic heritability is useful in that MZ twins’ genes and personalities are not affected by the environments: “As you can see, the MZ twins tend to be quite similar to each other regardless of whether they are raised with or separated from their twin brother or sister…The obvious explanation for this similarity is that the twins’ genes shaped their personalities in a similar manner regardless of the environments they grew up in” (Burger, 2011, p. 256).Burger, J.M. (2017). Personality, 10th ed. Mason, OH: Cengage Learning.Burger, J.M. (2011). Personality, 8th instructor’s edition. Belmont, CA: Wadsworth Advantages and disadvantages in using twins to analyze genetic heritability.