Which diagram is used to show the occurrence of a genetic trait in several generations of a family?

The correct diagram used to show the occurrence of a genetic trait across several generations of a family is a pedigree. A pedigree chart visually represents family relationships and displays how specific traits or genetic conditions are inherited over time. It typically includes symbols to denote males and females, and lines that connect family members to illustrate their connections, making it easier to track the presence of a trait through generations.

In genetics, pedigrees serve as essential tools for geneticists and medical professionals who are studying inherited traits, as they can help identify whether a trait is dominant, recessive, or linked to a particular sex. This information can be crucial for understanding inheritance patterns and predicting the likelihood of a trait appearing in future offspring.

Other diagrams mentioned, like a genogram, while similar, are more focused on a broader representation of familial relationships and do not specifically track genetic traits over generations. A chromosome map provides information about the physical structure of chromosomes, and a phylogenetic tree illustrates the evolutionary relationships between different species rather than tracking the inheritance of traits within a single family lineage.