Behavioral Genetics: Behavioral Traits, Twin and Adoption Methods

Ans. Attributes shown by the actions of an individual which specify their attitude and character are called behavioral traits. A particular species will showcase similar actions.

These are some of the behavioral traits which drive humans to success.

• Thinking strategically
• Initiation in bringing change
• Inspire others through activities
• Rectifying mistakes from experience
• Mindfulness and thoughtful
• Etiquettes
• Being respectful and humble 

Ans. Behavioral genetics is important to study, research, learn and understand humans or animals. It is essential to evaluate the abilities and disabilities of a gene, it provides us with the genetic and behavioral of the subject individual. It gives an idea of how a gene is distributed over the generations and how specific genes are transferred. 

Every species has unique behavioural genetics. Studies on this can tell the presence of different behavioral traits in an organism and how they are influenced by environmental factors and genetic factors. There are different methods for different qualities of an individual. For example, the twin method and the adoption methods help a parent understand how they can change their child’s behavior for the better. 

Ans. It is true that genes do influence our behavior. Our behaviour is derived from our genetic makeup. Genes cannot determine the entire behavior of an individual but they do influence it. Genetics deals with the study of genes, functions, and structure. It also showcases how genes flow from one generation to the other of that particular species. It also influences physical, emotional, and behavioral characteristics.

Genes that influence human behavior and determine behavioral traits are called behavioral genes. The environment in which the species is living along with the inherited genes determines the species behavior.

Example: Deer mice dig under the snow to the subnivean layer to stay warm and cache food. 

Ans. Thomas Hunt Morgan (1866-1945) is an American geneticist and Nobel Prize winner of 1933, is also known as “Father of experimental genetics” for his work on and discovery of linkage, the mutability of genes, crossing over, criss-cross inheritance, sex linkage, linkage maps, etc. He is called flyman of genetics because he selected Drosophila melanogaster as research material in experimental genetics. 

“The Theory of Gene '', his well-known book of genetics, was accepted as a distinct branch of biology. In 1910, he found the linkage and explored linked and unlinked genes. Morgan and Sturtevant in 1911 found that the frequency of crossing over between two linked genes is directly proportional to the distance between the two. 1% recombination is considered to be equal to 1 centiMorgan (cM) or 1 map unit.

He researched sex-linked inheritance and reported a white-eyed male Drosophila in a population of red-eyed and proved that gene of eye color is located on X-chromosome. The male passes its genes on X-chromosomes to the daughter while the son gets genes on X-chromosome from the female, It is called criss-cross inheritance.

Ans. Eysenck’s test was based on the twin method. In this, he used 25 pairs of fraternal twins along with 25 pairs of identical twins. Identical twins carry similar genes while fraternal twins have only half the similar genes. It is derived that if identical twins are raised in the same household, and so are fraternal twins then the characteristics of behavioral traits are determined largely by environmental factors that are about equally pronounced in both kinds of twins. 

The goal of identical versus fraternal twin studies is to know the significance of genetics for a particular characteristic. Identical twins share twice the genetic code shared between fraternal twins. Hence comparing the percentage of similarity between the two different kinds of twins, one can understand better the role that genetics play in determining the characteristics. Eysenck’s found that neuroticism was determined by genetics with 80% stemming from biology factors, and only 20% from environmental factors. 

Ans. Adoption studies are research methods for behavioural genetics. They are used to determine the percentage to which a variation in a trait can occur due to environmental and genetic influences. There are two types of adoption studies – the adoptee method and the familial method. The most dominant one of the methods is the comparison of pairs of genetically identical monozygotic identical twins who are adopted into different families. 

This shows that some traits are linked to genetics. In the adoptee method, the comparison is carried out between the adoptee and their biological and adoptive parents.  Similarities with the biological parent are heritable genetic effects, while similarity with the adoptive parent is related to the home environment generally called the shared environmental effect. 

The familial method compares the non-biological siblings which are raised in the same household. Comparison with non-biological siblings raised in the same household is attributed to the common environment effect because the siblings are biologically unrelated but have the home environment. 

Ans. Behavioral genetics is the study of individual differences developed through the interaction of genes and the environment. The two most common methods to study behavioural genetics are the twin and adoption methods. Actions that are commonly observed in individuals throughout any species are behavioral traits. 

Behavioral genetics is a field of research that uses genetic methods to find the nature, origin, and individual differences in the behavior of particular species. Eysenck derived that if identical twins are raised in the same household, and so are fraternal twins then the characteristics of behavioral traits are determined largely by environmental factors that are about equally pronounced in both kinds of twins. Adoption studies are used to determine the percentage to which a variation in a trait can occur due to environmental and genetic influences.