Final answer:
Incomplete dominance involves a blended phenotype in the heterozygote, codominance results in both alleles being equally expressed in the heterozygote, multiple alleles exist when a gene has more than two allele forms, polygenic traits are controlled by multiple genes, and sex-linked inheritance is tied to genes located on sex chromosomes.
Step-by-step explanation:
Comparing different forms of inheritance like incomplete dominance, codominance, multiple alleles, polygenic traits, and sex-linked inheritance can help explain deviations from the simple Mendelian model of genetics. In incomplete dominance, the phenotype of the heterozygotes is a blend of the phenotypes of the homozygous parents. An example is when a red flower and a white flower cross to produce offspring with pink flowers. In codominance, both alleles are fully expressed in the heterozygote, as seen in human blood type AB where both A and B alleles are equally expressed.
Multiple alleles refer to the existence of more than two alleles for a genetic trait within a population, such as the ABO blood group system in humans. However, an individual can still only have two of these alleles. Polygenic traits are controlled by the interaction of multiple genes, resulting in a wide range of phenotypes, such as human height or skin color. Lastly, sex-linked inheritance involves genes located on the sex chromosomes (typically the X chromosome), which results in different inheritance patterns between males and females, like in the case of color blindness or hemophilia. While incomplete dominance and codominance demonstrate different patterns of allele expression in heterozygotes, multiple alleles and polygenic traits highlight the genetic complexity beyond single-gene inheritance. Sex-linked inheritance underscores the role of chromosomal differences in genetic transmission. All these forms contribute to the diverse genetic inheritance patterns observed in nature.