Lesson 4 and 5 - Classical Genetics

Lesson Objectives

Content Objective: Be able to describe and identify recessive, codominant, and sex-linked traits from pedigree charts and be analysing the results of crosses.

Language Objective: Create punnet squares and pedigree charts showing recessive, codominance and sex-linked traits.

Book Reference: 116-119

Syllabus Details:

Understandings

Mendel discovered the principles of inheritance with experiments in which large numbers of pea plants were crossed
Sex is determined by sex chromosomes and autosomes are chromosomes that do not determine sex
Dominant alleles mask the effect of recessive alleles but codominant alleles have joint effects
Analysis of pedigree charts to deduce the pattern of inheritance of genetic diseases.

Application and Skills

Inheritance of ABO blood groups
Red-green colour blindness and haemophilia as examples of sex-linked inheritance
Inheritance of cystic fibrosis and Huntington’s disease
Construction of Punnett grids for predicting the outcomes of monohybrid genetic crosses
Comparison of predicted and actual outcomes of genetic crosses using real data
Chiasmata formation between non-sister chromatids can results in an exchange of alleles
Gene loci are said to be linked if on the same chromosome
Unlinked genes segregate independently as a result of meiosis.
Skill: Identification of recombinants in crosses involving two linked genes.
Identification of recombinants in crosses involving two linked genes