Genetica: geni associati e determinazione del sesso

In this high school biology lesson, we analyze linked genes and sex-linked inheritance. We retrace Thomas Hunt Morgan's historic experiments on Drosophila melanogaster and understand why his work revolutionized classical genetics. We begin with the concept of gene linkage: we'll see when two genes are found on the same chromosome and how this violates Mendel's laws. We then analyze the test cross (or backcross), a fundamental tool for revealing recombination frequency, and study the role of crossing-over in the partial separation of linked genes. ⚙️ In the second part, we address chromosomal sex determination: we compare the XY system of mammals, the X0 system of insects, and the ZW system of birds. We delve into the role of the SRY gene on the Y chromosome and discuss sex determination by ploidy in bees and cases of hermaphroditism. 📌 We conclude with *sex-linked genes*, analyzing their location and the asymmetry between the X and Y chromosomes, with concrete examples from Drosophila. We follow each step with diagrams and guided reasoning, so as to consolidate each concept in a lasting way. 📌 INDEX: 0:00 Introduction 0:22 Genetic Linkage 0:59 Morgan and Drosophila 1:58 Morgan's Experiments 3:24 Test Cross or Backcross 5:32 Morgan's Results 6:50 Linked Genes and Crossing-Over 7:52 Linked Genes in P. Sativum 9:08 Chromosomal Sex Determination 10:14 Y Chromosome and the SRY Gene 10:54 XY System and X0 System 11:56 ZW System 12:37 Sex Determination in Bees 13:17 Hermaphroditism 13:52 Sex-Linked Genes 14:48 Examples in Drosophila ---------------------------------------------------------------------------------------------------------------------------------------------------- 🔔 SUBSCRIBE TO THE CHANNEL and turn on notifications to stay updated on new videos.    / @scienzeconchris   Playlist:    • Biologia (Scuola Superiore)   #Genetics #Sex-LinkedInheritance #LinkedGenes