According To The Pedigree Chart Which Statement Must Be True
Introduction
A pedigree chart is a diagrammatic representation of an individual's family history, which is used to track the inheritance of genetic traits over generations. It is a powerful tool used by geneticists and genealogists to study the patterns of inheritance of various traits in a family. The pedigree chart shows the relationships between family members, and each individual's genetic makeup.
Understanding the Pedigree Chart
The pedigree chart is used to determine the likelihood of an individual inheriting a specific trait, such as hair color or eye color. The chart shows the inheritance of a trait through generations and can be used to identify patterns of inheritance, such as autosomal recessive or dominant inheritance or X-linked inheritance.
The chart typically includes the names of the family members, their gender, and their relationships with each other. The chart also includes symbols that represent specific traits, such as circles for females, squares for males, and shaded shapes for individuals with the trait being studied.
Types of Inheritance
There are three main types of inheritance patterns that can be identified using the pedigree chart: autosomal dominant, autosomal recessive, and X-linked inheritance.
Autosomal dominant inheritance occurs when a gene that causes a trait is located on an autosomal chromosome (i.e., not on the X or Y chromosome) and one copy of the gene is sufficient to cause the trait to be expressed. In this type of inheritance, an affected individual will have at least one affected parent.
Autosomal recessive inheritance occurs when a gene that causes a trait is located on an autosomal chromosome and two copies of the gene are required for the trait to be expressed. In this type of inheritance, an affected individual will have two unaffected parents who are carriers of the gene.
X-linked inheritance occurs when a gene that causes a trait is located on the X chromosome. This type of inheritance is more common in males than females because males only have one X chromosome. In this type of inheritance, an affected male will have an affected mother, and all of his daughters will be carriers of the gene.
Which Statement Must Be True?
The pedigree chart can be used to determine the likelihood of an individual inheriting a specific trait. However, not all statements that can be made about a pedigree chart are true. The statement that must be true depends on the specific traits being studied and the inheritance pattern being observed.
For example, if the trait being studied is autosomal dominant, then the statement that must be true is that an affected individual will have at least one affected parent. If the trait being studied is autosomal recessive, then the statement that must be true is that an affected individual will have two unaffected parents who are carriers of the gene. If the trait being studied is X-linked, then the statement that must be true is that an affected male will have an affected mother, and all of his daughters will be carriers of the gene.
Conclusion
The pedigree chart is a powerful tool used by geneticists and genealogists to study the patterns of inheritance of various traits in a family. It can be used to determine the likelihood of an individual inheriting a specific trait and to identify patterns of inheritance, such as autosomal dominant, autosomal recessive, and X-linked inheritance. The statement that must be true depends on the specific traits being studied and the inheritance pattern being observed.