Module 5: Mendelian Genetics and Genetic Disorders

Have you ever looked in the mirror and wondered which traits you inherited from your mother and which came from your father? You might have dark hair and your brother(s) and/or sister(s) have blonde hair. How could this have occurred? In this module, you will learn about the study of how traits are passed from parent to offspring, or genetics. Along with your exploration of genetics, physical traits, and heredity, you will learn how some diseases and medical conditions are passed down from one generation to the next.

Getting Started

Physical characteristics, or traits, define many of the features of your body. These physical traits were determined by genetics. The first thing you may notice when you look at someone could be their hair color, eye color, or height. When fertilization occurs, each parent may contribute dominant or recessive genes that will determine the offspring's physical traits. Before you begin learning about genetics, see how many dominant and recessive traits you have. Access the Dominant and Recessive Characteristics Table and check off all your dominant and recessive traits.

Key Vocabulary

To view the definitions for these key vocabulary terms, visit the course glossary.

allele	genetics	nondisjunction
autosomes	heredity	pedigree
carrier	heterozygous	phenotype
chromosomes	homozygous	polygenic traits
codominant	incomplete dominance	Punnett square
dihybrid cross	karyotype	recessive
dominant	monohybrid cross	sex-linked traits
gene	monosomy	trisomy