Final answer:
The person from whom a pedigree is initiated is known as the proband, typically indicated by an arrow in the pedigree chart. The proband is the individual whom the geneticist studies to understand the inheritance patterns of traits or genetic disorders in a family.
Step-by-step explanation:
The person from whom a pedigree is initiated is called the proband and is usually designated by an arrow. This is the individual whose phenotype (traits or genetic condition) is being studied, typically because they have a trait or disorder that is of interest to the geneticist or researcher compiling the pedigree. The proband is also known as the index case or patient zero within the pedigree chart.
Pedigree analysis is a tool that helps in understanding the inheritance pattern of genes across generations within a family, especially when studying genetic disorders and traits. In the chart, males are represented by squares, females by circles, and a horizontal line connecting a male and female indicates their offspring, which are connected to them by vertical lines. A pedigree can provide insights into the mode of inheritance of a trait, such as autosomal dominant, autosomal recessive, X-linked dominant, or X-linked recessive, among others.