Module 6
1. Module 6
1.2. In this Module
Module 6—Mendelian Genetics: The Transmission of Traits to the Next Generation
In This Module
Inquiry Question: What are the basic rules and steps that affect the transmission of genetic characteristics to the next generation?
There are ten lessons in Module 6.
Most of the lessons are designed to take you 80 minutes to complete; however, some lessons may take longer because of the significance of the concept being covered in the lesson. The suggested lesson times do not include the time needed to complete such activities as “Try This,” “Watch and Listen,” assignments, practice questions, review, or research.
This module corresponds to Chapter 17, pages 584 to 621, in your textbook. You will be referred to the relevant pages in each lesson.
Lesson 1: Theories and Terminology of Inheritance
In this lesson you will explore and become familiar with the language of genetics. You will be introduced to a nineteenth century monk, Gregor Mendel, and learn why he is considered the Father of Genetics.
You will consider the following focusing questions:
- What is the basic language of genetics?
- How does the work of Mendel explain the basics of classical genetics?
Lesson 2: Mendel’s Laws and Monohybrid Crosses
In this lesson, you will learn the patterns of inheritance that Mendel first discovered in pea plants. You will become familiar with techniques and conventions used by geneticists to trace the inheritance of traits from one generation to the next.
You will consider the following focusing questions:
- What are the simple principles of single trait inheritance?
- How can genotype be determined from phenotype?
Lesson 3: Multiple Alleles and Incomplete Dominance Crosses
In this lesson, you will explore traits that do not follow Mendel’s patterns of simple dominance, but can still be explained by his laws. You will understand how genes can have more than two alternate forms.
You will consider the following focusing questions:
- What happens when one allele is not completely dominant over another?
- How does having more than two alleles for a gene affect the possible phenotypes for a trait?
Lesson 4: Dihybrid Crosses
In this lesson, you will learn how to follow the inheritance of two separate traits at the same time. As you follow two traits you will understand how the movement of alleles for one trait does not affect the alleles of another trait during the formation of gametes.
You will consider the following focusing question:
- How do scientists track the inheritance of more than one trait at a time?
Lesson 5: Probability
In this lesson, you will learn how to predict the genetic outcome of future generations by examining numbers and ratios. Patterns can give the likelihood of a trait remaining hidden or being expressed.
You will consider the following focusing question:
- How can ratios be used to analyze types of inheritance or to predict the possibility of a trait appearing in the next generation?
Lesson 6: Chromosomal Theory and Sex-Linked Inheritance
In this lesson, you will begin to explore inheritance patterns that do not follow Mendel’s laws. You will see how some traits occur more frequently in one gender over another, and are said to be sex-linked.
You will consider the following focusing questions:
- Why do some traits appear more frequently in one gender than the other?
- How did Thomas Hunt Morgan’s work provide experimental support for the chromosomal theory of inheritance?
Lesson 7: Genes and the Environment
In this lesson, you will examine the effect the environment may have on the expression of genes.
You will consider the following focusing question:
- How does the environment affect the expression of genes?
Lesson 8: Polygenetic Traits
In this lesson, you will study traits that are controlled by many genes. You will recognize inheritance patterns that result in gradual changes in phenotypes, and you will understand that the expression of one gene can turn the expression of another on or off.
You will consider the following focusing question:
- How might multiple genes combine to form a single trait?
Lesson 9: Crossing Over Frequencies and Gene Mapping
In this lesson, you will learn how genes that are found on the same chromosome are termed linked because they tend to move together. You will learn how crossing over in meiosis allows scientists to map the relative location of genes that are found on the same chromosome.
You will consider the following focusing questions:
- How does crossing-over in chromosomes relate to finding the position of genes?
- What is the importance of knowing the location of specific genes on a chromosome?
Lesson 10: Plant, Animal, and Human Genetics
In this lesson, by learning to create and analyze pedigrees, you will be able to track the inheritance of rare genetic diseases through families.
You will consider the following focusing question:
- What technologies exist to help explain and predict the inheritance of traits in breeding programs and/or family histories?