Chapter-4: Principles of Inheritance and Variation

Heredity and variation: Mendelian inheritance; deviations from Mendelism (incomplete dominance, co-dominance, multiple alleles and inheritance of blood groups, pleiotropy).  

Elementary idea of polygenic inheritance; chromosome theory of inheritance; chromosomes and genes.  

Sex determination: in humans, birds, and honey bee; linkage and crossing over.  

Sex-linked inheritance: haemophilia, colour blindness.  

Mendelian disorders in humans: thalassemia; chromosomal disorders in humans (Down’s syndrome, Turner’s, and Klinefelter’s syndromes).