Final answer:
Mendel's rules of inheritance do not fully explain the patterns of heredity. Incomplete dominance, codominance, recessive lethals, multiple alleles, and sex linkage are some of the phenomena that deviate from Mendel's model. These concepts involve traits influenced by multiple genes, interactions between alleles, and patterns of inheritance that do not follow simple dominant or recessive patterns.
Step-by-step explanation:
The inheritance patterns of many traits cannot be fully explained by Mendel's rules of dominance, segregation, and independent assortment. While Mendel's experiments with pea plants laid the foundation for our understanding of heredity, subsequent research has revealed additional complexities in inheritance patterns that cannot be accounted for by Mendelian genetics alone.
Phenomena such as incomplete dominance, codominance, recessive lethals, multiple alleles, and sex linkage explain the deviations from Mendel's model of inheritance. These concepts involve traits that are influenced by multiple genes, interactions between alleles, and patterns of inheritance that do not follow simple dominant or recessive patterns.
For example, incomplete dominance occurs when the heterozygous genotype results in a phenotype that is intermediate between the two homozygous genotypes. Codominance occurs when both alleles in a heterozygous genotype are fully expressed, resulting in a phenotype that displays characteristics of both alleles. Recessive lethals are alleles that are only lethal when homozygous, and therefore do not follow the laws of dominance. Multiple alleles refer to the existence of more than two alleles for a particular gene, as seen in the ABO blood type system. Lastly, sex linkage refers to the inheritance of genes located on the sex chromosomes, which can lead to different patterns of inheritance.