“Probability Theory and Its Applications in Genetics: Unraveling Genetic Inheritance and Variability’’

UNIVERSITY OF AGRICULTURAL SCIENCES, BANGALORE

DEPARTMENT OF GENETICS AND PLANT BREEDING

M.Sc. Seminar – GPB 581 (0+1)

“Probability Theory and Its Applications in Genetics: Unraveling Genetic Inheritance and Variability’’

 

Probability is the likelihood of occurrence of an event. The concept of probability is basic to understanding many principles of classical genetics, such as segregation and independent assortment¹. There are two basic rules of probability. The first one is the Multiplicative Rule: if the events A and B are independent, the probability that they occur together, denoted as P(A and B), is P(A) × P(B). The second one is the Additive Rule: if the events A and B are independent, the probability that at least one of them occurs, denoted as P(A or B), is P(A) + P(B) – [P(A) × P(B)]².

The probabilities of different combinations of independent events can be computed easily by using the appropriate binomial expansion. The set of terms, along with their coefficients, obtained by expanding the general binomial is known as the binomial expansion¹.

Probability plays a crucial role in calculating gene and genotypic frequencies in populations, particularly in population genetics and evolutionary biology. The Hardy–Weinberg law is the fundamental principle of population genetics and provides the basis for studying Mendelian populations¹.

Statistical analysis allows researchers to compare observed data, such as numbers obtained from breeding experiments, with predicted values. If the comparison is unfavorable—that is, the observed data are not in line with the predicted values—the statistic will exceed a critical threshold and the genetic hypothesis will be rejected. If the statistic is below this number, the hypothesis will be accepted².

Genetics is inherently probabilistic, as biological inheritance and gene expression are influenced by chance events. The application of probability theory enables scientists to make predictions about genetic traits, disease risks, and evolutionary changes. From Mendelian inheritance to modern genomic research, probability theory remains a cornerstone of genetic analysis.

REFERENCES

1. Singh, B. D., 2023. Fundamentals of Genetics. 6th edition, pp. 166–179.

2. Snustad, D. P. and Simmons, M. J., 2006. Principles of Genetics. 4th edition, pp. 47–59.