Written primarily for students embarking on an undergraduate bioscience degree, this primer will review the essential biological concepts that underpin any programme of more advanced study and give early-stage undergraduates the opportunity to review topics about which they may feel under-prepared or less confident.Genetic medicine has entered an era of rapid expansion. It is no longer just relevant to families affected by rare congenital disorders, but has the potential to affect the diagnosis and treatment of most common complex diseases.The successful application of new genetic science in the decades ahead will depend on the next generation of undergraduates or university applicants, who are now planning their careers as Biologists and Clinicians.This primer explores core concepts about heredity and genome analysis, illustrates current clinical practice with case-histories, and discusses the potentials and pitfalls of personalised medicine.