The following pedigree illustrates the inheritance of ringed...

Name: Problem 27, Chapter 6: Genetics: A Conceptual Approach
Uploaded: 2020-07-04T07:26:42-08:00
Duration: 55 s
Channel: Jorge Villanueva
Description: The following pedigree illustrates the inheritance of ringed hair, a condition in which each hair is differentiated into light and dark zones. What mode or modes of inheritance are possible for the ringed-hair trait in this family?

The following pedigree illustrates the inheritance of ringed hair, a condition in which each hair is differentiated into light and dark zones. What mode or modes of inheritance are possible for the ringed-hair trait in this family?

Key Concepts

X-linked Inheritance

X-linked inheritance describes traits associated with genes located on the X chromosome. These traits can show a bias in expression between males and females due to the difference in the number of X chromosomes, with males often being more severely affected when a mutant allele is present.

Autosomal Recessive Inheritance

Autosomal recessive inheritance requires an individual to receive two copies of a mutant allele, one from each parent, to exhibit the trait. This pattern often results in traits that may skip generations and appear in siblings, with both sexes equally affected.

Pedigree Analysis

Pedigree analysis is a method used to study the transmission of traits through a family tree, allowing geneticists to deduce potential inheritance patterns. By tracking which individuals express a trait and how it is passed down through generations, one can infer whether the trait is likely dominated by a single gene, and whether it might follow dominant, recessive, or sex-linked patterns.

Modes of Inheritance

Modes of inheritance refer to the patterns by which genetic traits are transmitted from parents to offspring. In classical genetics, these modes include autosomal dominant, autosomal recessive, and X-linked inheritance, each of which has distinct characteristics in terms of trait expression and generational appearance.

Autosomal Dominant Inheritance

Autosomal dominant inheritance occurs when a single copy of a mutant allele on one of the autosomes is sufficient to cause the phenotype. Such traits typically appear in every generation and affect males and females equally, as well as often being transmitted by an affected individual to about half of their offspring.

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