SCIENCE AND AGRO STUDIES

Linkage :-   When two alleles present together on a chromosome are inherited together, it is called linkage. Note:- Crossing over can be up to 50% only. Linkage groups:-  A linkage group is a linearly arranged group of linked genes which are normally inherited together except for crossing over. Types of linkage:- i. Complete linkage:-  > The genes located on the same chromosome do not separate and are inherited together over the generations due to the absence of crossing over.  > Complete linkage allows the combination of parental traits to be inherited as such.  > It is rare but has been reported in male Drosophila and some other heterogametic organisms. ii. Incomplete linkage:- > Genes present in the same chromosome have a tendency to separate due to crossing over and hence produce recombinant progeny besides the parental type.  > The number of recombinant individuals is usually less than the number expected in independent assortment. ...

1. Gynandromorph:-  In Drosophila, sometimes half of the body is male and half is female. This state is called Gynandromorph. Gynandromorphs:-  ड्रोसोफिला मक्खी में कभी कभी शरीर का आधा भाग नर व आधा भाग मादा होता है। इस अवस्था को Gynandromorph कहते हैं। 2. Pleiotropism:-   When a single gene controls more than one genetic traits, then this is called Pleiotropism. Such a gene is called as pleiotropic gene.  Example:-   Sickle Cell Anemia Disease (Autosomal recessive disorder) प्लीओट्रोपिज्म:-  जब एक जीन एक से अधिक आनुवंशिक लक्षणों को नियंत्रित करता है तो इस प्रक्रिया को Pleiotropism कहते हैं।  उदाहरण:-  Sickle Cell Anemia Disease (Autosomal recessive disorder) 3. Crossing over:-  The process in which genes are exchanged between the non-sister chromatids of homologous chromosomes is called crossing over. The term gene exchange was given by T. H. Morgan. जीन विनिमय:- वह प्रक्रिया जिसमें समजात गुणसूत्रों की Non – sister chromatids के मध्य जी...