Who had proposed the chromosomal theory of inheritance?
Answers
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Chromosomal Theory of Inheritance and Genetic Linkage
Objectives:
By the end of this section, you will be able to:
Discuss Sutton’s Chromosomal Theory of Inheritance
Describe genetic linkage
Explain the process of homologous recombination, or crossing over
Describe how chromosome maps are created
Calculate the distances between three genes on a chromosome using a three-point test cross
Long before chromosomes were visualized under a microscope, the father of modern genetics, Gregor Mendel, began studying heredity in 1843. With the improvement of microscopic techniques during the late 1800s, cell biologists could stain and visualize subcellular structures with dyes and observe their actions during cell division and meiosis. With each mitotic division, chromosomes replicated, condensed from an amorphous (no constant shape) nuclear mass into distinct X-shaped bodies (pairs of identical sister chromatids), and migrated to separate cellular poles.
Chromosomal Theory Of Inheritance
The speculation that chromosomes might be the key to understanding heredity led several scientists to examine Mendel’s publications and re-evaluate his model in terms of the behavior of chromosomes during mitosis and meiosis. In 1902, Theodor Boveri observed that proper embryonic development of sea urchins does not occur unless chromosomes are present. That same year, Walter Sutton observed the separation of chromosomes into daughter cells during meiosis (Figure). Together, these observations led to the development of the Chromosomal Theory of Inheritance, which identified chromosomes as the genetic material responsible for Mendelian inheritance.
Part a is a photo of Walter Sutton. Part b is a photo of Theodor Boveri.
(a) Walter Sutton and (b) Theodor Boveri are credited with developing the Chromosomal Theory of Inheritance, which states that chromosomes carry the unit of heredity (genes).
The Chromosomal Theory of Inheritance was consistent with Mendel’s laws and was supported by the following observations:
During meiosis, homologous chromosome pairs migrate as discrete structures that are independent of other chromosome pairs.
The sorting of chromosomes from each homologous pair into pre-gametes appears to be random.
Each parent synthesizes gametes that contain only half of their chromosomal complement.
Even though male and female gametes (sperm and egg) differ in size and morphology, they have the same number of chromosomes, suggesting equal genetic contributions from each parent.
The gametic chromosomes combine during fertilization to produce offspring with the same chromosome number as their parents.
- Walter Sutton and Theodor Boveri are credited with developing the Chromosomal Theory of Inheritance, which states that chromosomes carry the unit of heredity (genes).