Skip to Content

Genetics and a Transcontinental Romance


Pamela Kalas
Departments of Zoology and Botany
The University of British Columbia


Annika is a PhD student from Sweden who spends two years in the Solomon Islands to complete her fieldwork. During her stay in the South Pacific she experiences a few surprises related to the hair color not only of the locals, but also of her own baby girl. Throughout this case study, which integrates classical genetics, population genetics and introductory genomics, students investigate different aspects of the "blond hair" phenotype. They start by exploring its possible origins as well as reasons for its geographic distribution, and then examine its somewhat surprising inheritance using both classical genetics and genome sequencing data. Finally, students use allele and genotype frequency data from the literature to evaluate whether there are mating preferences based on hair color in the Melanesian population. This case is based on the finding that Melanesian people have a unique mutant allele of the TYRP1 gene, which is responsible for their relatively frequent blond hair. Three different versions of Part III allow instructors to tailor the case to the level of their students.


  • Describe at least two distinct mechanisms that can lead to genetic variation (a) between and (b) within populations of the same species.
  • Develop multiple hypotheses to explain an observation in a given scenario.
  • Propose possible genetic and genomic experiments to test a hypothesis, and predict the results if (a) the hypothesis is accurate and (b) if the hypothesis is inaccurate.
  • Analyze genetic data (including pedigrees) to determine the mode of inheritance of a trait, including the number of genes and alleles involved, dominance relationships, and sex linkage (or lack thereof).
  • Given the functions of two or more gene products that control a phenotype, predict the phenotypic effects of changes to one or more of the genes involved.
  • Given the necessary allele and phenotype frequencies, determine whether a large population is mating randomly with respect to a phenotype of interest.
  • Develop a general idea of how classical genetics, molecular genetics, population genetics, and genomics, can be utilized to address questions about a given phenotype (e.g., hair color).
  • Describe, in general terms, how a GWAS is conducted and its purpose.
  • Read and summarize the results shown in a Manhattan plot.


Allele frequency; mutation; genome-wide association study; GWAS; hair color; blond; blonde; multi-gene inheritance; phenotype distribution; TYRP1; Solomon Islands; Melanesia;

Topical Areas


Educational Level

Undergraduate lower division



Type / Methods




Subject Headings

Biology (General)  |   Genetics / Heredity  |   Evolutionary Biology  |  

Date Posted


Teaching Notes

Case teaching notes are password-protected and access to them is limited to paid subscribed instructors. To become a paid subscriber, begin the process by registering.

Teaching notes are intended to help teachers select and adopt a case. They typically include a summary of the case, teaching objectives, information about the intended audience, details about how the case may be taught, and a list of references and resources.

Answer Key

Answer keys for the cases in our collection are password-protected and access to them is limited to paid subscribed instructors. To become a paid subscriber, begin the process by registering.