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

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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

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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. The college was started in the city, and later shifted to its present location. Outside the city on

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Bangalore-Honnavar highway in 1948.Today Sahyadri Science College is one of the premier educational institute in the Malenadu area, South Karnataka.

It is prestigious one too more than 2000 students were studying in this premier institute. The location of the study area is shown in Map1.

Sahyadri Science College Campus

Results and Discussion A short term study on human traits with simple inheritance patterns was conducted in Sahyadri Science College campus. In the present study human genetic traits were enumerated in the Table 1-7

Table 1: Total Number of Dominant and Recessive Traits Number of Number of Total Number of Sl. No. Physical Traits Dominant Traits Recessive Traits Individuals 1 Cheeks 78 390 468 2 Ear Lobes 294 174 468 3 Eye Brow Size 158 310 468 4 Eye Lashes 148 320 468 5 Eye Shape 240 228 468 6 Eye Sight 384 84 468 7 Face Shape 197 271 468 8 Finger Mid Digit Hair 199 269 468 9 Freckles 60 408 468 10 Hair Colour 334 134 468 11 Hair Form 76 392 468 12 Hair Whorl 280 188 468 13 Hand Clasping 234 234 468 14 Hand Hair 207 261 468 15 Hitchhicker’s Thumb 282 186 468 16 Little Finger 162 306 468 17 Tongue Folding 294 174 468 18 Tongue Rolling 306 162 468 19 Vision 356 112 468 20 Widow’s Peak 134 334 468

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Table 2: Percent Frequency of Dominant Individuals Percent Frequency of Dominant Sl. No. Physical Traits Individuals 1 Hair Whorl 59.82 % 2 Hair Form 16.23 % 3 Cheeks 16.66 % 4 Tongue Rolling 65.38 % 5 Tongue Folding 62.82 % 6 Eye Lashes 31.62 % 7 Widow’s Peak 28.63 % 8 Ear Lobes 62.82 % 9 Hair Colour 71.36 % 10 Normal Vision 76.06 % 11 Eye Sight 82.05 % 12 Freckles 12.82 % 13 Little Finger 34.61 % 14 Hitchhicker’s Thumb 60.25 % 15 Hand Clasping 50.0 % 16 Finger Mid Digit Hair 42.52 % 17 Hand Hair 44.23 % 18 Face Shape 42.09 % 19 Eye Brow Size 33.76 % 20 Eye Shape 51.28 % Table 3: Percent Frequency of Recessive Individuals Percent Frequency of Recessive Sl. No. Physical Traits Individuals 1 Cheeks 83.33 % 2 Ear Lobes 37.17 % 3 Eye Brow Size 66.23 % 4 Eye Lashes 68.37 % 5 Eye Shape 48.71 % 6 Eye Sight 17.94 % 7 Face Shape 57.90 % 8 Finger Mid Digit Hair 54.47 % 9 Freckles 87.17 % 10 Hair Colour 28.63 % 11 Hair Form 83.76 % 12 Hair Whorl 40.17 % 13 Hand Clasping 50.0 % 14 Hand Hair 55.76 % 15 Hitchhicker’s Thumb 39.74 % 16 Little Finger 65.38 % 17 Normal Vision 23.93 % 18 Tongue Folding 37.17 % 19 Tongue Rolling 34.61 % 20 Widow’s Peak 71.36 %

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Table 4: Percent Frequency of Dominant Male Percent Frequency of Dominant Sl. No. Physical Traits Male 1 Cheeks 16.88 % 2 Ear Lobes 63.63 % 3 Eye Brow Size 54.54 % 4 Eye Lashes 33.76 % 5 Eye Shape 64.93 % 6 Eye Sight 87.01 % 7 Face Shape 63.63 % 8 Finger Mid Digit Hair 63.63 % 9 Freckles 11.68 % 10 Hair Colour 80.51 % 11 Hair Form 16.88 % 12 Hair Whorl 61.03 % 13 Hand Clasping 59.74 % 14 Hand Hair 66.23 % 15 Hitchhicker’s Thumb 53.24 % 16 Little Finger 49.53 % 17 Normal Vision 70.12 % 18 Tongue Folding 76.62 % 19 Tongue Rolling 76.62 % 20 Widow’s Peak 25.97 % Table 5: Percent Frequency of Recessive Male Percent Frequency of Recessive Sl. No. Physical Traits Male 1 Cheeks 83.11 % 2 Ear Lobes 36.36 % 3 Eye Brow Size 45.45 % 4 Eye Lashes 66.23 % 5 Eye Shape 35.06 % 6 Eye Sight 12.98 % 7 Face Shape 36.36 % 8 Finger Mid Digit Hair 36.36 % 9 Freckles 88.31 % 10 Hair Colour 19.48 % 11 Hair Form 83.11 % 12 Hair Whorl 38.96 % 13 Hand Clasping 40.25 % 14 Hand Hair 33.76 % 15 Hitchhicker’s Thumb 46.75 % 16 Little Finger 50.64 % 17 Normal Vision 29.87 % 18 Tongue Folding 23.37 % 19 Tongue Rolling 23.37 % 20 Widow’s Peak 74.02 %

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Table 6: Percent Frequency of Dominant Female Percent Frequency of Dominant Sl. No. Physical Traits Female 1 Cheeks 33.76 % 2 Ear Lobes 62.42 % 3 Eye Brow Size 36.94 % 4 Eye Lashes 30.57 % 5 Eye Shape 60.50 % 6 Eye Sight 79.61 % 7 Face Shape 47.13 % 8 Finger Mid Digit Hair 47.77 % 9 Freckles 13.37 % 10 Hair Colour 66.87 % 11 Hair Form 15.92 % 12 Hair Whorl 59.61 % 13 Hand Clasping 45.22 % 14 Hand Hair 49.68 % 15 Hitchhicker’s Thumb 63.69 % 16 Little Finger 27.38 % 17 Normal Vision 78.98 % 18 Tongue Folding 56.05 % 19 Tongue Rolling 59.87 % 20 Widow’s Peak 29.93 % Table 7: Percent Frequency of Recessive Female Percent Frequency of Recessive Sl. No. Physical Traits Female 1 Cheeks 83.43 % 2 Ear Lobes 37.57 % 3 Eye Brow Size 63.05 % 4 Eye Lashes 69.42 % 5 Eye Shape 39.49 % 6 Eye Sight 20.38 % 7 Face Shape 52.86 % 8 Finger Mid Digit Hair 52.22 % 9 Freckles 86.62 % 10 Hair Colour 33.12 % 11 Hair Form 84.07 % 12 Hair Whorl 40.76 % 13 Hand Clasping 54.77 % 14 Hand Hair 50.31 % 15 Hitchhicker’s Thumb 36.30 % 16 Little Finger 72.61 % 17 Normal Vision 21.01 % 18 Tongue Folding 40.12 % 19 Tongue Rolling 43.94 % 20 Widow’s Peak 70.06 %

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The present survey revealed that No two individuals are similar. They differ from one another in morphological and behavioral traits. These differences arise due to genetic and environmental factors. In the survey, it was observed that traits vary from person to person. Between 40- 90% of the population have free-hanging earlobes, can roll their tongue, earlobe, hand clasping, blue eyes, chick dimple, widows peak, second toe longest, short index finger, mid digital hair and six finger. Because these traits occur most often within the population they are called high frequency traits. The rate of frequency is a statistical term that helps us to determine how often an inherited trait occurs. Frequency is important in discovering how much of the population differs (or is similar) from one geographical area to another. The aspect of relating morphogenetic traits are of great important to many areas such as forensic pathology, anthropology and other related disciplines; as such it will be useful to determine the frequency of these tribes and regions which could aid in the identification of human. References 1. Beckman, L., and J.A. Book. 1959. Distribution and inheritance of mid-digital hair in Sweden. Hereditas45: 215-220. 2. Beckman, L., J.A. Book, and E. Lander.1960. An evaluation of some anthropological traits used in paternity tests. Hereditas 46: 543-569. 3. Boas, H. M. 1918. Inheritance of eye color in man. American Journal of Physical Anthropology 2: 15-20. 4. Brues, A. M. 1975. Rethinking human pigmentation. American Journal of Physical Anthropology 43: 387-391. 5. Cell biology, genetics, molecular biology, evolution and ecology. P.S Varma, V.K Agarwal, lst edition 1974, S.Chan and company LTD. Ram nagar, Delhi. 6. Davenport, G. C., and C. B. Davenport. 1907. Heredity of eye color in man. Science 26: 589-592. 7. Freire-Maia, N. A. Quelce-Salgado, and A. Freire-Maia. 1958. Hand clasping in different ethnic groups. Human Biology 30: 281-291. 8. Genetics A.M Winchester, 3rd edition, barrens and Nobel publ. new York, London. 9. Genetics Alice Marcus, reader department of zoology, holy cross, Tamil nadu. 10. Heredity. An introduction to genetics. A.M Winchester, 2nd edition, Barrens and Nobel books publishers. NEW YORK, San Francisco, London. 11. Kaplan, A. R. 1964. Genetics of relative toe lengths. ActaGeneticaeMedicaeetGemellologiae 13: 295-304. 12. Lee, J. W. 1955. Tongue-folding and tongue-rolling in an American Negro population sample. Journal of Heredity 46: 289-291. 13. Liu, T. T., T. C. Hsu. 1949. Tongue-folding and tongue-rolling in a sample of the Chinese population. Journal of Heredity 40: 19-21. 14. Martin, N. G. 1975. No evidence for a genetic basis of tongue rolling or hand clasping. Journal of Heredity 66: 179-180. 15. Wiedemann, H-R. 1990. Cheek dimples. American Journal of Medical Genetics 36: 376. 16. Winchester, A. M. 1951. Genetics: A survey of the principles of heredity. Houghton Mifflin Company, Cambridge, MA.

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