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sex linkage codominance
A LevelBiology~5 min read
Overview
This lesson explores sex linkage, a special case of inheritance where genes are located on sex chromosomes, and codominance, a non-Mendelian inheritance pattern where both alleles in a heterozygote are fully expressed, resulting in a distinct phenotype.
Introduction to Sex Linkage
Sex linkage refers to the inheritance of genes located on the sex chromosomes, primarily the X and Y chromosomes in humans. Unlike autosomal genes, the inheritance patterns of sex-linked genes differ between males and females due to their different sex chromosome complements (XX for females, XY for ...
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Key Concepts
- Sex Linkage: Inheritance pattern of genes located on sex chromosomes (X or Y).
- X-linked Inheritance: Inheritance of genes located specifically on the X chromosome.
- Y-linked Inheritance: Inheritance of genes located specifically on the Y chromosome.
- Codominance: An inheritance pattern where both alleles in a heterozygote are fully and equally expressed, resulting in a phenotype that shows characteristics of both homozygous parents.
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Exam Tips
- →When tackling sex-linked inheritance problems, always clearly state the genotypes of parents and offspring using appropriate notation (e.g., X^H X^h for a carrier female, X^h Y for an affected male).
- →For codominance questions, remember that the heterozygous phenotype will display *both* traits distinctly, not an intermediate blend. Use superscript notation for alleles (e.g., I^A, I^B) to avoid confusion.
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