Linked Genes Challenge Mendel’s Principle of Independent Assortment
- Mendel’s principle of independent assortment states that alleles for different genes segregate independently during gamete formation.
- However, this only applies to genes on different chromosomes or those far apart on the same chromosome.
- Linked genes, located close together, do not assort independently because they tend to stay together during meiosis.
Chromosome Diagrams Visualize Gene Linkage
- To represent linked genes, geneticists use diagrams of homologous chromosomes, with alleles marked as tick marks alongside vertical lines representing the chromosomes.
- Genes located close together on the same chromosome tend to be inherited as a unit because they are physically linked.
- During meiosis, homologous chromosomes separate, but linked genes often travel together unless crossing over occurs.
Why Linked Alleles Fail to Assort Independently
- Linked genes are physically located on the same chromosome, so they tend to be inherited together.
- This physical linkage prevents independent assortment during gamete formation.
- Only when crossing over occurs between linked genes can recombination produce new allele combinations.
How does the discovery of gene linkage challenge Mendel's laws of inheritance? What does this reveal about the complexity of biological systems?
Self review- List two key features of linked genes.
- Why do linked genes not sort independently?
