Mendelian Genetics Overview

Mendelian Inheritance

• Traits are determined when offspring receive one allele from each parent.
• Dominant traits can overshadow recessive traits.

Recessive Traits

• Recessive traits can be masked by dominant traits.
• Alleles are different versions of the same gene in an organism.

Incomplete Dominance

• Inheritance pattern where neither allele is dominant.
• Offspring show an intermediate form of the trait, blending features from both parents.

Principle of Dominance

• Dominant traits mask the expression of recessive traits.
• Incomplete dominance contrasts Mendelian inheritance by blending traits.

Codominance

• Both alleles are dominant and expressed equally in the phenotype.
• Example: Blood type is influenced by antigens present on blood cells.

Discovery of Blood Types (1898)

• New methods developed for preserving and transporting blood for transfusions.
• Improvement in blood transfusion safety standards.
• Elements of blood can now be separated using centrifuge technology.
• Plasma can be preserved through freezing techniques.

Blood Type Characteristics

• Blood type exemplifies codominance, as both alleles contribute to the phenotype.
• Rh factor indicates the presence of the rhesus protein in blood; Rh+ blood contains this protein.
• Rh- blood lacks the rhesus protein.

Blood Donation Compatibility

• Type O blood is known as the universal donor due to its compatibility.
• Type AB blood is recognized as the universal recipient, able to accept any blood type.
• Rh+ individuals can receive both Rh+ and Rh- blood, while Rh- individuals can only accept Rh- blood.

Polygenic Inheritance

• Involves multiple genes influencing a single trait, located at various loci across different chromosomes.
• Polygenic traits demonstrate a non-Mendelian inheritance pattern, leading to a range of phenotypes.