We explain what the chromosomal theory of inheritance formulated by Sutton and Boveri is. Also, how it is based on Mendel's laws.
What is the chromosomal theory of inheritance?
The chromosomal theory of inheritance or chromosomal theory of Sutton and Boveri It is the scientific explanation of the transmission of certain characters through the genetic code that contains the living cell, which occurs between one generation of individuals and the next.
This theory It was developed by scientists Theodor Boveri and Walter Sutton in 1902 . Despite the distance between them, Boveri (German, 1862-1915) and Sutton (American, 1877-1916) independently postulated the same conclusions based on previously existing knowledge about heredity and cellular functioning.
It was a debated and controversial theory until 1915, when experiments with flies Drosophila melanogaster by the American scientist Thomas Hunt Morgan (1856-1945) completely confirmed them.
The chromosomal theory of inheritance studied genes, that is, the DNA segments that encode specific proteins, also called “hereditary factors” in his studies on heredity Gregor Mendel (1822-1884). Specifically, postulated that genes are located within the chromosomes of the cell located in turn within the cell nucleus.
The existence of chromosomes was already known and their replication during cell division was known, but from then on they were known much better: it was known that they come in homologous pairs, one from the mother and one from the father, so reproductive cells or gametes must provide each individual with exactly half of the genetic material.
This theory allowed us to understand why certain characters are inherited and others are not that is, why one allele is transmitted and another is not, since they are independent of each other, being located on different chromosomes. For example, the chromosome that contains information about the sex of the individual is different from the chromosome that contains information about the color of the individual's eyes, etc.
Mendel's Laws
The main antecedent of the chromosomal theory of inheritance is the studies of Gregor Mendel who carried out a series of experiments and monitoring among pea plants, managing to formulate the well-known Mendel's Laws of inheritance in 1865.
Their experiences were fundamental to understanding how genetic characteristics are transmitted from one generation to the next. First of all, discovered that there are characters (genes) of two types: dominant (AA) or recessive (aa) depending on whether it is manifest in the individual or not, in the latter case being a carrier of the non-manifest gene.
In this way, Mendel proposed the existence of “pure” (homozygous) individuals, whether dominant or recessive (AA or aa), and other heterozygotes resulting from genetic mixing and transmission (Aa), for each specific hereditary character.
This approach was the first human attempt to describe the laws that govern genetics, and although its results were recognized much later, it was a revolutionary contribution for its time, the foundation of everything that would come later.
References
- “Sutton and Boveri chromosome theory” on Wikipedia.
- “The chromosomal basis of heredity” in Khan Academy.
- “Chromosome theory of inheritance” in Southern Biology.
- “Chromosomal Theory of Inheritance and Genetic Linkage” in Lumen Learning.
- “The Chromosomes in Heredity” in The Encyclopaedia Britannica.
