Pedigree Analysis – Class 12 | Chapter – 5 | Biology Short Notes Series PDF

Pedigree Analysis: It is a scientific approach to studying the inheritance of human genes. Pedigree analysis can be used to easily understand family history and the inheritance of dominant and recessive traits. With the help of a pedigree chart, one can easily identify dominant and recessive traits and also the carriers of these traits.

Diagrammatic Representation of Pedigree Analysis Charts

Relationships are presented diagrammatically in a pedigree chart. 

Pegigree Analysis Diagram

  • The parents are connected by a horizontal line, with a vertical line leading to their offspring.
  • A horizontal zip line connects all the offspring of the same parents. They are placed from left to right according to their order of birth.
  • Twin offspring are connected by a triangle.
  • If an offspring is no more, there is a line across it.
  • A small triangle represents if the offspring was aborted or has not yet been born.

Types of Pedigree Analysis

Based on linked chromosomes, pedigree analysis is classified into:

1) Sex-linked pedigree

It is subdivided into:

  • X-linked pedigree
  • Y-linked pedigree

Even the X-linked pedigree is further divided into:

  • X-linked dominant pedigree
  • X-linked recessive pedigree

2) Autosomal pedigree

  • Autosomal dominant pedigree
  • Autosomal recessive pedigree


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By Team Learning Mantras