15introduction

GeneralBiologyOnline

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Ch. 15 Contents

General
---------Biology-----------------------------------------------------
------------------Online--------------------------------------- Ch. 15 Chromosomal Basis of Inheritance

Introduction

The first three sections of this chapter discuss three historical developments:

Mendel's discoveries are explained by the behavior of chromosomes in meiosis
Genes are located along the length of chromosomes
Genes on the same chromosome tend to wind up in the same gamete and to be inherited together (called "linked" genes)

These facts are obvious to us based on our understanding of chromosomes, mitosis and meiosis. However, Mendel had no knowledge of these cellular mechanisms, as they were discovered later in the 1800's and early 1900's.

We will skip over these historical developments and cover:

how chromosomes determine the gender of the offspring
how genes located on sex chromosomes are inherited, e.g. hemophilia
how mistakes in meiosis cause Down syndrome, caused by an extra chromosome # 21
how chromosome breakage and reattachment cause serious abnormalities

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