Reviewed by: Mary Anne Clark, PhD
(genetics) One of the Mendelian Laws of Inheritance stating that the two members of a pair of alleles separate during gamete formation. Consequently, each gamete contains only one member of every pair of genes.
In Gregor Mendel’s paper describing his work on the breeding and analysis of thousands of garden peas, he was able to come up with the founding principles of inheritance, later summarized as Mendel’s Laws of Inheritance. These laws are the Law of Segregation, the Law of Independent Assortment, the Law of Dominance, and the Law of Unit Characters.
The Law of Segregation holds that a zygote has two copies of each gene, one provided by each parent and combined by the union of parental gametes during fertilization. Mendel, who had no knowledge of chromosomes, proposed that the determining factors of inheritance are discrete “unit factors” (now called genes) that maintain their integrity from the time that the zygote is formed through the time that it matures and produces its own gametes. During gamete formation, the members of these paired “unit factors” segregate from one another and enter into separate gametes.
Mendel’s proposition was verified when chromosomes were discovered and meiosis was extensively delineated in the following years. If the genes were located on chromosomes, then during Anaphase I of meiosis, the two members of the pair would separate as the homologous chromosomes moved apart from each other toward the opposite ends of the dividing cell.
- Law of Purity of Gametes
|MENDEL’S PRINCIPLES OF HEREDITY – QUIZ |
Print this quiz for your students to answer. The first part is a recall of Gregor Mendel’s principles of heredity. The second part is a multiple-choice test about alleles and sex chromosomes.