Refers to similarities in DNA sequences and gene compositions
Exist between family members due to shared genetic inheritance
Can be observed between individuals of the same population or ethnic group
Influence presence of common genetic traits and susceptibility to diseases
Important for studying genetic variations and heritability of traits.
Limitations
The correlational nature of the study prevents establishing cause-and-effect relationships. Specific genes were not isolated and tested in the study. Self-reported information about life events and depressive symptoms may introducebias. The reliance on clinical diagnoses reported by interviewees over the phone raises validity concerns.