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30: Chromosomes and Linkage

Last updated

Nov 12, 2024
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- 29.4: Key Terms
- 30.1: Introduction

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30.1: Introduction
The gene is the physical unit of inheritance, and genes are arranged in a linear order on chromosomes. The behaviors and interactions of chromosomes during meiosis explain, at a cellular level, the patterns of inheritance that we observe in populations. Genetic disorders involving alterations in chromosome number or structure may have dramatic effects and can prevent a fertilized egg from developing altogether.
30.2: Chromosomal Theory and Genetic Linkage
The Chromosomal Theory of inheritance, proposed by Sutton and Boveri, states that chromosomes are the vehicles of genetic heredity. Neither Mendelian genetics nor gene linkage is perfectly accurate; instead, chromosome behavior involves segregation, independent assortment, and occasionally, linkage. Sturtevant devised a method to assess recombination frequency and infer the relative positions and distances of linked genes on a chromosome on the basis of the average number of crossovers.
30.3: Practice- Linkage, Recombination Frequency and Genetic Maps
30.4: Linked Genes Violate the Law of Independent Assortment
30.5: Key Terms
30.6: Chapter Summary

Image Source: 10 Drosophila Salivary Chromosomes. Elissa Lei, Ph.D. @ NIH

Description: Drosophila salivary gland polytene chromosomes. Highly replicated polytene chromosomes of the Drosophila salivary gland stained with DAPI (blue) and antibodies directed against gypsy insulator proteins Su(Hw) (green) and Mod(mdg4)2.2 (red).

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