Molecular Evolution and Genetic Analysis

This page explores molecular evolution, focusing on the origin of opsin genes, and introduces techniques for genetic analysis.

The evolution of opsin genes, responsible for color vision, is presented as a case study in molecular evolution. Through processes like gene duplication, mutation, and transposition, a single ancestral pigment gene diversified into multiple opsin genes (S, M, L) over evolutionary time.

Example: The duplication and subsequent mutation of an ancestral opsin gene led to the development of trichromatic vision in some primates, including humans.

The page also covers the endosymbiotic theory, explaining the origin of eukaryotic organelles like mitochondria and chloroplasts from prokaryotic ancestors. This theory is crucial for understanding the evolution of complex cellular structures.

Definition: Endosymbiosis is a symbiotic relationship in which one organism lives inside the cells of another, as seen in the origin of mitochondria and chloroplasts.

Restriction Fragment Length Polymorphism (RFLP) analysis is introduced as a technique for detecting genetic variations. This method involves cutting DNA with restriction enzymes, amplifying the fragments, and separating them by electrophoresis.

Vocabulary: Restriction enzymes are proteins that cut DNA at specific sequences, used in genetic engineering and analysis techniques like RFLP.

The page concludes with an overview of horizontal gene transfer in prokaryotes, including transformation, transduction, and conjugation. These mechanisms allow genetic material to be exchanged between unrelated organisms, contributing to bacterial evolution and adaptation.

Highlight: Horizontal gene transfer can occur between different species, playing a significant role in prokaryotic evolution and the spread of antibiotic resistance.

Understanding these concepts and techniques is essential for students studying Génétique cours Terminale and preparing for exams like Sujet bac SVT génétique et évolution corrigé.