{"id":195709,"date":"2022-06-17T15:28:07","date_gmt":"2022-06-17T09:58:07","guid":{"rendered":"https:\/\/www.aakash.ac.in\/blog\/?p=195709"},"modified":"2023-03-07T01:23:45","modified_gmt":"2023-03-06T19:53:45","slug":"what-is-chromosomal-theory-of-inheritance-and-who-proposed-it","status":"publish","type":"post","link":"https:\/\/www.aakash.ac.in\/blog\/what-is-chromosomal-theory-of-inheritance-and-who-proposed-it\/","title":{"rendered":"What is Chromosomal Theory of Inheritance and Who Proposed it?"},"content":{"rendered":"

As a biology student, you have often heard the term ‘genes’, ‘chromosomes’, or ‘inheritance.’ You may also be quite aware of Mendel’s famous biologist. He was the first to propose the fundamental law of inheritance. But, do you know what it was exactly? Or who detected that genes lie in the chromosome and precisely where genes lie in the cells? And what is the theory that proposed such an idea?<\/span><\/p>\n

This article will help you with the answers to all these questions. Read till the end to get more information.<\/span><\/p>\n

In 1843, the father of modern genetics, Gregor Mendel, initiated studying parentage. Due to the absence of advanced microscopes during that period, chromosomes had not been practised, and his work got disregarded by scientists for a long time. There are more reasons for that, like lack of communication mediums.<\/p>\n

Later, after the invention of advanced microscopes, some scientists started to study his work and re-evaluate his models in terms of chromosomal practices.<\/span><\/p>\n

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Chromosome<\/h3>\n

The DNA molecule is bundled into a thread-like structure in each cell nucleus. These structures are called chromosomes. Each chromosome is made up of histones, i.e., tightly coiled DNA around protein. That holds up the structure of chromosomes.<\/span><\/p>\n

Chromosomes help ensure that DNA is reproduced and distributed properly during cell division. In humans, there are 46 chromosomes present in each individual’s body. These 46 chromosomes are arranged in 23 pairs. And out of 23 pairs, 22 pairs of chromosomes are called autosomes. Other than autosomes, human has one pair of sex chromosomes called an allosome.<\/span><\/p>\n

Chromosomes are the location of genes, and genes are the stretches of DNA that specify proteins. Therefore, they are interlinked with each other. Or precisely, genes are part of chromosomes.<\/span><\/p>\n

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The Chromosomal Theory of Inheritance<\/h3>\n

The hypothesis that chromosomes might be the way to understand extraction led several scientists to investigate Mendel’s publications. They reanalyse his model regarding the conduct of chromosomes during meiosis and mitosis. In 1900, scientists could carefully observe cell division due to the advancement in microscopes. It led to the discovery of some double and divided structures in the nucleus just before each cell division. They called them chromosomes.<\/span><\/p>\n

Later, in 1902, Theodore Boveri and Walter Sutton studied the chromosomes’ actions and found similarities in-between the bearing of genes and chromosomes. They use this movement of chromosomes to explain Mendel’s theory. Their observations taught them that chromosomes are found in pairs. Similarly, genes also occur in pairs. The two allelomorphs of a gene pair are located on equivalent sites on homologous chromosomes.<\/span><\/p>\n

Boveri and Sutton argued that the pairing and separation of chromosomes would separate a pair of genes they carried. Sutton consolidated the knowledge of chromosomal partitioning with Mendelian principles and called it the chromosomal theory of inheritance.<\/span><\/p>\n

Later, Thomas Hunt Morgan and his colleagues followed this idea of the chromosomal theory of inheritance and provided the required experimental verification. Hence, it has become the foundational genetic theory that acknowledges chromosomes as the messenger of genetic material.<\/span><\/p>\n

The main points of this theory are as follows:<\/span><\/p>\n

    \n
  • Gametes (sperm and egg) transfer hereditary characters from one generation to another.<\/span><\/li>\n
  • The two allelomorphs of a gene pair are placed on homologous sites on the comparable chromosomes.<\/span><\/li>\n
  • Chromosomes and genes are both found in pairs.<\/span><\/li>\n
  • The nucleus is the area of hereditary characters.<\/span><\/li>\n
  • Homologous chromosomes get nervous during meiosis and get separated to pass into different cells, which becomes the basis of separation and independent diversity during meiosis.<\/span><\/li>\n
  • The gametes having haploid sets of chromosomes fuse to amalgamate the diploid state.<\/span><\/li>\n<\/ul>\n

    Check our visual story on Principles of Inheritance & variations<\/strong><\/p>\n

    Principles of Inheritance & Variation: Class 12 CBSE Revision Notes<\/a><\/p><\/blockquote>\n