In this article we will discuss about:- 1. Meaning of Crossing Over 2. Frequency of Crossing Over 3. Factors 4. Molecular Mechanism. Meaning of Crossing Over: Crossing over may be defined as an interchange of corresponding chromosomal parts between members of a homologous chromosome resulting in a recombination of genes. One, two or more fragments may be interchanged during crossing [...]
The following points highlight the eight main criticisms for Lyon’s hypothesis. Criticism # 1. That XO, XXX, XY, XX etc. individual differ among themselves suggesting that the entire X chromosome is not genetically inactive. If it were so, an XX and XXX female would have had no difference at all. From various chemical stigmata it seems that a part of [...]
The three examples of autosome-linked genetic disease are: 1. Sickle Cell Anemia 2. Alkaptonuria (Black Urine Disease) 3. Phenylketonuria. Example # 1. Sickle Cell Anemia: Sickle cell anemia is an inherited abnormal disease caused by mutation of autosomal gene. The red blood cells of certain individuals have peculiar property of undergoing reversible alterations in shape when subjected to changes in [...]