The golden-white bears (Ursus americanus kermodei) of British Columbia, Canada, are not polar bears. They are a subspecies of black bear called Kermode spirit bears. Their distinctive, majestic fur is caused by a mutation in the MC1R gene, which is only found in this subspecies. Caused by a single nucleotide substitution mutation in the DNA of the bears, this mutant allele is recessive, meaning that it must be inherited from both parents for the phenotype (golden-white fur) to be displayed.
Substitution mutations are those in which a nucleotide is spontaneously switched for another during DNA replication. In this case, the mutation means that an adenine nucleotide is produced rather than a guanine nucleotide. This missense mutation leads to coding for a different amino acid, and therefore an altered tertiary structure of the resulting MC1R protein.
Your organisation does not have access to this article.
Sign up today to give your students the edge they need to achieve their best grades with subject expertise
Subscribe
