- Important works of Sutton
- Mendel and his influence on Sutton's works
- Chromosomal theory of heredity
- Contributions to cytogenetics
- References
Walter Stanborough Sutton (1877-1916) was a well-known American geneticist and biologist born in 1877 in New York. Throughout his childhood he studied in different public schools until he entered the University of Kansas in 1896 to study engineering. However, the death of his little brother from typhoid fever will mark his life forever causing Sutton to decide to dedicate himself to medicine.
Walter Sutton's contributions have contributed significantly to the fields of genetics and biology, having been one of the pioneers in the study of cytogenetics and having developed the chromosomal theory of inheritance.
Influenced by Clarence Erwin McClung, an American biologist famous for discovering the role chromosomes play in sex determination, Sutton becomes an instructor in zoology and begins his work in cytogenetics.
After graduating in 1900 and beginning his graduate studies, Sutton set about formulating his important chromosomal theory of heredity, continuing to work in the fields of genetics, medicine, and biology.
He finally obtained a doctorate in medicine in 1907 and worked as a surgeon until his death in 1916 from acute appendicitis.
Important works of Sutton
In 1902, he published his work "The spermatogonial division of Brachystola Magna" (On the morphology of the chromosomal group Brachystola Magna), after having carried out various experiments with grasshoppers and discovering the great value that these species had in carrying out cytogenetic studies.
Because of the length of their cells, grasshoppers became the best species to investigate cell structure. With his experiment Sutton discovered the presence of identifiable individual chromosomes, which were found in pairs during meiosis.
With this publication, he demonstrated the presence of homologous chromosomes, pairs of chromosomes with similar structure and size, of which one pair comes from the maternal line and the other from the paternal line.
In 1903, one of the most recognized works in the field of biology came to light; "The chromosomes in heredity".
With this publication Sutton discovers that the Mendelian laws of inheritance could also be applied to chromosomes at the cellular level, and as a result of this discovery he develops his main contribution: the chromosomal theory of inheritance.
Mendel and his influence on Sutton's works
Sutton's works and his famous theory could be carried out thanks to the investigations previously raised by the Austrian monk Gregor Mendel.
There was no correlation between the behavior of the chromosomes and the hereditary factors defined by Mendel, until Sutton made his hypothesis by specifying that the hereditary factors must be found in the chromosomes.
Chromosomal theory of heredity
Sutton established that all chromosomes exist in pairs that are very similar to each other, stating that each gamete or sex cell contributes one chromosome from each pair by halving its genetic material when a new cell is formed during meiosis.
Each fertilized ovum is the sum of the parental chromosomes, which, and in this statement lies their theory, are capable of controlling inheritance. The chromosomal theory states that Mendelian alleles are located on chromosomes.
Each chromosome is the carrier of a group of genes, understood as the hereditary factors or physical units that make up the chromosomes. Hence, each gene has a biological characteristic that will determine the traits of an individual.
The two main postulates of the theory indicate that:
-The chromosomes are the carriers of the genes of an individual.
-The chromosomes of the parents during meiosis unite, becoming homologous chromosomes that exchange their genetic material, originating a single phenotype. Sutton defines the phenotype as the set of characteristics that are externally manifested and that are responsible for the color of eyes, hair or physical features of an individual.
This theory has also been called the "Sutton-Boveri Hypothesis", since it was the biologist Theodor Boveri who previously established the individuality and permanence of chromosomes.
Contributions to cytogenetics
Cytogenetics is today an important branch of genetics in charge of studying human chromosomes, becoming a great tool when performing chromosomal diagnoses of patients.
Walter Flemming in 1882 would be the first researcher to show the illustrations of the human chromosome, although Sutton was the main pioneer of the studies of chromosomes and genes.
Sutton is considered the father of cytogenetics, having introduced into the field of genetics the importance of chromosomes and how they influence and determine the hereditary traits of individuals.
References
- Aguirre, J. Retrieved on August 20, 2017 from blogspot.com
- Encyclopedia Britannica. Walter Sutton. Retrieved on August 20, 2017 from britannica.com
- Classical genetics: mendelism and chromosomal theory of inheritance. Retrieved on August 19, 2017 from files.wordpress.com
- What is cytogenetics? Retrieved on August 20, 2017 from todo-en-salud.com
- Sutton, W. (1902). On the morphology of the chromosome group in Brachystola Magna. Retrieved on August 19, 2017 from esp.org
- Sutton and Morgan theory. Retrieved on August 19, 2017 from google.com