Description: Quantitative genetics is the study of the inheritance of traits that are determined by multiple genes, in contrast to Mendelian genetics, which focuses on traits controlled by a single gene. This field deals with the continuous variation of phenotypic characteristics, such as height, weight, or disease resistance, which cannot be easily classified into discrete categories. Quantitative genetics employs statistical and mathematical tools to analyze the relationship between genetic variation and phenotypic variation, allowing researchers to understand how genes interact with each other and with the environment to influence observable traits. This approach is fundamental in the genetic improvement of crops and livestock, as well as in genetic association studies in humans. Quantitative genetics also relies on bioinformatics, which provides computational methods to handle and analyze large volumes of genetic data, facilitating the identification of loci associated with complex traits. In summary, quantitative genetics is essential for unraveling the complexity of the inheritance of multifactorial traits and has a significant impact on various areas of biology and medicine.
History: Quantitative genetics began to take shape in the early 20th century when scientists started applying statistical principles to genetics. One of the most important milestones was Ronald A. Fisher’s work in the 1910s, who developed mathematical models to describe the inheritance of complex traits. Fisher, along with other pioneers such as Sewall Wright and J.B.S. Haldane, laid the foundations of modern quantitative genetics. In 1930, Fisher published ‘The Genetical Theory of Natural Selection’, where he integrated genetics with evolutionary theory, allowing for a deeper understanding of how traits are transmitted and evolve in populations. Throughout the 20th century, quantitative genetics solidified as a key field in biology, especially in crop improvement and animal breeding.
Uses: Quantitative genetics has multiple applications in various fields. In agriculture, it is used to improve crops by selecting for desirable traits, such as disease resistance or yield. In animal breeding, it allows for the selection of individuals with optimal characteristics for meat, milk, or wool production. In medicine, quantitative genetics is applied in association studies to identify genes related to complex diseases, such as diabetes or cardiovascular diseases. Additionally, it is fundamental in research on genetic variability in human populations and in species conservation.
Examples: An example of quantitative genetics in action is the maize improvement program where plants with higher yield are selected over several generations, using statistical analyses to assess the inheritance of traits such as ear size and pest resistance. Another case is the study of height in humans, where multiple loci associated with this trait have been identified, demonstrating how quantitative genetics can help understand the complexity of multifactorial traits.
