Chromosomal Theory of Inheritance by Sutton

The question asks about the concept developed by Sutton that combined the knowledge of chromosomal segregation with Mendelian principles.

During the early 20th century, after Mendel's work was rediscovered, scientists began to understand the physical basis of inheritance. Thomas Hunt Morgan and Walter Sutton were key figures in this field. Sutton, in particular, observed the behavior of chromosomes during cell division, specifically meiosis.

Sutton noticed that chromosomes behave in a way that perfectly aligns with Mendel's laws of inheritance. He saw that:

• Chromosomes exist in pairs, just like Mendel's factors (alleles).
• During gamete formation (meiosis), homologous chromosomes separate and segregate into different gametes, which explains Mendel's Law of Segregation.
• Different pairs of chromosomes assort independently during meiosis, which explains Mendel's Law of Independent Assortment.

By connecting the behavior of chromosomes to the patterns of inheritance described by Mendel, Sutton proposed that chromosomes were the carriers of Mendel's factors (genes). This groundbreaking idea unified cytology (the study of cells, especially chromosomes) with genetics (the study of heredity). Sutton called this integrated concept the Chromosomal theory of inheritance.

Let's look at the options provided:

• Chromosomal theory of inheritance: This aligns directly with the historical development and the name given to the concept by Sutton.
• Chromosomal theory of Segregation: While chromosomal segregation is a key part, the theory encompasses more than just segregation; it links chromosome behavior to all of Mendelian inheritance.
• Chromosomal theory of Hereditary: This is a less precise term; "inheritance" is the standard term used in the context of this theory.
• Chromosomal theory of Behaviour: Chromosomal behavior is central, but the theory explains inheritance *through* this behavior.

Therefore, the concept developed by Sutton that united chromosomal segregation knowledge with Mendelian principles is known as the Chromosomal theory of inheritance.