International Journal of Scientific Research and Review ISSN NO: 2279-543X “A Survey of human traits with simple inheritance patterns in Sahyadri Science College Campus Shivamogga” Sindhu N Naik[1] and Ranjith Y[2] Sahyadri Science College, Shivamogga – 577203. Email : [email protected] Abstract Physical traits are observable characteristics determined by specific segments of DNA called genes. Multiple genes are grouped together to form chromosomes, which reside in the nucleus of the cell. Every cell (except eggs and sperm) in an individual’s body contains two copies of each gene. This is due to the fact that both mother and father contribute a copy at the time of conception. This original genetic material is copied each time a cell divides so that all cells contain the same DNA. Genes store the information needed for the cell to assemble proteins, which eventually yield specific physical traits. This study was conducted from July to September 2018. The methodology used in this study was combination of descriptive and interviews and observations of the individual. The assessment of morphogenetic trait of tongue rolling, earlobe, hand clasping, blue eyes, chick dimple, widows peak, second toe longest, short index finger, mid digital hair and six finger in relation to genotype was studied in the Shivamogga. Keywords: Physical traits, Sahyadri Science College Campus, Introduction Most genes have two or more variations, called alleles. For example, the gene for hairline shape has two alleles – widow’s peak or straight. An individual may inherit two identical or two different alleles from their parents. When two different alleles are present they interact in specific ways. For the traits included in this activity, the alleles interact in what is called a dominant or a recessive manner. The traits due to dominant alleles are always observed, even when a recessive allele is present. Traits due to recessive alleles are only observed when two recessive alleles are present. For example, the allele for widow’s peak is dominant and the allele for straight hairline is recessive. If an individual inherits: • Two widow’s peak alleles (both dominant), their hairline will have a peak • One widow’s peak allele (dominant) and one straight hairline allele (recessive), they will have a widow’s peak • Two straight hairline alleles (recessive), their hairline will be straight. A widespread misconception is that traits due to dominant alleles are the most common in the population. While this is sometimes true, it is not always the case. For example, the allele for Huntington’s disease is dominant, while the allele for not developing this disorder is recessive. At most, only 1 in 20,000 people will get Huntington’s; most people have two recessive, normal alleles. While a few traits are due to only one gene (and its alleles), most human genetic traits are the product of interactions between several genes. The traits listed on the next pages have commonly been presented as being determined by single genes. However, several have been shown to involve more than one gene, and research studies do not agree 102 Volume 8, Issue 2, 2019 Page No: 102 International Journal of Scientific Research and Review ISSN NO: 2279-543X on the inheritance pattern of others. All people are recognizably human, but no one is exactly like anyone else, not even an identical twin. The basis for the similarity and the reasons for the diversity that coexist in all species have puzzled and intrigued people for thousands of years. Several human traits may be used to demonstrate the individuality in humans. They are controlled by a single gene with two alleles; each allele producing a distinct phenotype. Alleles are different expressions of the same gene. All can be used to demonstrate Mendel's Law of Segregations of Biology contents40 Genetic Inheritance in Humans. a) Eder/Shutter stock b) Cordelia Molloy/Photo Researchers, Inc./Science Source c) Will & Deni McIntyre/Science Source Common traits that are often described in textbooks and used to teach Mendelian inheritance, but in fact are much more complex, include hitchhiker's thumb (a), tongue rolling (b), and attached earlobes (c). There are more than 7 billion people in the world, and almost everyone looks at least slightly different from everyone else. How is this amount of variation possible? With the exception of identical twins, the gene combinations we receive from our parents vary from sibling to sibling. These individual genotypes that make up the genetic profile of the individual are part of the reason why no two humans look exactly the same. Only identical multiples (e.g., identical twins, triplets, etc.) share a genotype, but their phenotypes, or physical appearances, still differ due to other factors, including complex genetic interactions and interactions with the environment. However, look at a multi-generational family photo and it is clear that relatives share characteristics such as freckles, a cleft chin or attached earlobes. Thousands of human traits are at least somewhat inheritable and run in families. Is there a reliable way to predict whether these traits will be inherited? For more than 100 years, scientists have applied the basic principles of inheritance that G J Mendel described in pea plants to a large number of human traits, ranging from seemingly unimportant traits such as whether one's hair forms a widow's peak to genetic disorders that can cause debilitating disease and death. Many of these traits are readily observable and have served as teaching tools and textbook examples for decades. For example, eye color, the ability to bend back the thumb nearly 90 degrees(known as hitchhiker's thumb), the ability to roll ones tongue into a U-shape, or whether one's earlobes are attached or free were all thought to have simple Mendelian inheritance patterns . Even though many people(including textbook authors and biology teachers) still portray these traits as having simple Mendelian inheritance characteristics such as dominant and recessive alleles of a single gene, the inheritance patterns of most of these traits are in fact much more complex. Even some traits thought to have somewhat more complicated but still predictable inheritance, such as male pattern baldness (originally thought to be a sex-linked trait passed from the mother's father to her sons), turn out to be determined by much more complex interactions of multiple genes and the environment. Organisms have different number of chromosomes, some organisms has as few as two, while some have up to a thousand. Humans have 23 different chromosomes and each of those has an identical partner chromosome. The paired chromosomes that are similar are considered to be homologues and each chromosome has the same genes. These two genes interact with each other to produce the characteristic they are assigned to and the two copies of the genes are called alleles. When the two alleles are considered together, they make up a single gene. When a gene is 103 Volume 8, Issue 2, 2019 Page No: 103 International Journal of Scientific Research and Review ISSN NO: 2279-543X composed of two identical alleles it is considered homozygous. When the gene is composed of two different alleles, the gene is heterozygous. G J Mendel, an European monk, became known as the “father of modern genetics” for his study of inheritance of traits in pea plants. Through selective cross-breeding of different traits (tall, short, purple flower, white flower, smooth seed) of pea plants Mendel discovered the basic principles of heredity. Over many generations of breeding pea plants, Mendel discovered that certain traits show up in offspring without any blending of parent characteristics. For example, when pollen from tall plants was used to pollinate the flowers of short plants, all the offspring were tall. There was no mixing of tall and short plants. In the previous example, the trait of “tall” which exclusively appeared in the first generation (F1) and reappeared in the second generation (F2) was identified as the dominant trait. The second generation also revealed the “short” trait that was absent in the F1 generation. This trait that was absent in the F1 generation but present in the F2 generation was identified as the recessive trait. Unfortunately, Mendel did not know about DNA, chromosomes, or genes and was unable to understand the biological and physical processes that allowed inheritance to occur and the importance of his work was not recognized until many years later. Materials and Methods This study was conducted from July to September 2018. The methodology used in this study was combination of descriptive and interviews and observations of the individual. The assessment of morphogenetic trait of tongue rolling, earlobe, hand clasping, blue eyes, chick dimple, widows peak, second toe longest, short index finger, mid digital hair and six finger in relation to genotype was studied in the below study area. 468 subjects comprising of 314 females and 154 males, aged 18-61 years were randomly selected in the study area. Cheeks, Ear Lobes, Eye Brow Size, Eye Lashes, Eye Shape, Eye Sight, Face Shape, Finger Mid Digit Hair, Freckles, Hair Colour, Hair Form, Hair Whorl, Hand Clasping, Hand Hair, Hitchhicker’s Thumb, Little Finger, Tongue Folding, Tongue Rolling, Vision and Widow’s Peak were recorded. All the collected information were accumulated and analyzed by MS-Excel and then presented in textual, tabular and graphical forms to understand the present status of the trait of the individual of the studied area. The formula is given below: Number of observed Percent frequency = x 100 Total Population Study Area The study area was selected for our survey is Sahyadri Science College campus, Shivamogga. Shivamogga has its geographical location from 13°17' North altitude to 14°30' from 74°37' to 75°50' East latitude.