Inheritance of Genetic pattern

Inheritance patterns explain how traits are passed from parents to offspring. These patterns are governed by Mendelian and non-Mendelian principles.

Mendelian Inheritance

Overview:

• Based on Gregor Mendel’s experiments with pea plants.
• Involves traits controlled by single genes on autosomal chromosomes.

Key Laws:

1. Law of Segregation:

   • Each individual has two alleles per gene, one from each parent, which separate during gamete formation.

2. Law of Independent Assortment:

   • Alleles of different genes assort independently during gamete formation, creating various allele combinations.

Modes of Inheritance:

1. Autosomal Dominant:

   • A single dominant allele causes the trait.
   • Offspring have a 50

2. Autosomal Recessive:

   • Two recessive alleles are required to express the trait.
   • Offspring have a 25
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3. X-Linked Dominant:

   • Affects the X chromosome.
   • Males have a 50

4. X-Linked Recessive:

   • More common in males (one X chromosome).
   • Females need two copies of the recessive allele to express the trait.

Non-Mendelian Inheritance

Overview:

• Involves complex genetic interactions that don’t follow Mendel’s laws.

Types:

1. Codominance:

   • Both alleles are equally expressed (e.g., AB blood type).
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2. Incomplete Dominance:

   • Neither allele is dominant, resulting in a blended phenotype (e.g., red + white flowers = pink).

3. Polygenic Inheritance:

   • Multiple genes contribute to a single trait (e.g., skin color, height).

4. Epistasis:

   • One gene’s expression is affected by another gene.
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5. Mitochondrial Inheritance:

   • Traits passed via maternal mitochondrial DNA.

6. Genomic Imprinting:

   • Gene expression varies based on whether the gene is inherited from the mother or father due to epigenetic modifications.

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