polymorphism

Examples of polymorphism in the following topics:

• No Perfect Organism

  • Therefore, the process of evolution is limited by a population's existing genetic variance, the physical proximity of alleles, non-beneficial intermediate morphs in a polymorphic population, and non-adaptive evolutionary forces.
  • Furthermore, natural selection can be constrained by the relationships between different polymorphisms.
  • Color and pattern morphs of the grove snail, Cepaea nemoralis.The polymorphism, when two or more different genotypes exist within a given species, in grove snails seems to have several causes, including predation by thrushes.

• Class Scyphozoa

  • Scyphozoans are free-swimming, polymorphic, dioecious, and carnivorous cnidarians with a prominent medusa morphology.
  • The life cycle of these animals can be described as polymorphic because they exhibit both a medusal and polypoid body plan at some point .

• Genetic Maps

  • In general, a good genetic marker is a region on the chromosome that shows variability or polymorphism (multiple forms) in the population.
  • Some genetic markers used in generating genetic maps are restriction fragment length polymorphisms (RFLP), variable number of tandem repeats (VNTRs), microsatellite polymorphisms, and the single nucleotide polymorphisms (SNPs).
  • Certain regions of the chromosome that are subject to polymorphism will lead to the generation of the unique banding pattern.
  • Microsatellite polymorphisms are similar to VNTRs, but the repeat unit is very small; thus, it is often referred to as short tandem repeats(STRs).

• Class Cubozoa and Class Hydrozoa

  • Cubozoans live as box-shaped medusae while Hydrozoans are true polymorphs and can be found as colonial or solitary organisms.
  • Animals in this class are polymorphs: most exhibit both polypoid and medusoid forms in their lifecycle, although this is variable.

• Physical Maps and Integration with Genetic Maps

  • An expressed sequence tag (EST) and a single sequence length polymorphism (SSLP) are common STSs.

• Phylum Cnidaria

  • Some cnidarians are polymorphic, having two body plans during their life cycle.