ganese uptake and metabolism in crops and livestock

1. Sources and Maintenance of Variation in Crop and Livestock for Improvement: a) Genetic Variation: It is essential for the improvement of livestock and crops. Genetic variation is caused by the mutation of DNA sequences, environmental influences on the genes, genetic crossover through sexual reproduction, etc. b) Hybridization: This involves cross-breeding of different varieties or species of plants or animals to create hybrid varieties with desirable traits. c) Mutation Breeding: By introducing mutations artificially, new variants of crops and livestock can be created. d) Clonal Propagation: In plants, this allows for producing exact copies of a plant with desirable traits. Maintenance of variation in crops and livestock can be achieved through strategies like cross-breeding, selection, and preservation of diverse breeds and varieties, among others. 2. Various Structural and Numerical Chromosomal Aberrations and Their Effects on Man: a) Structural Aberrations: - Deletion: It is a loss of part of a chromosome, leading to missing genes. For example, Cri-du-chat syndrome in humans is caused by a deletion in chromosome 5. - Duplication: An extra copy of a part of a chromosome is present. It can lead to conditions like Charcot-Marie-Tooth disease type 1A. - Translocation: A segment of one chromosome breaks off and attaches to another chromosome. This is found in cancers and certain genetic disorders like Down Syndrome. - Inversion: A segment of a chromosome is reversed end to end. It can lead to increased risks of miscarriage or infertility. b) Numerical Aberrations: - Monosomy: Loss of a single chromosome (2n-1). It leads to various syndromes such as Turner syndrome. - Trisomy: Gain of a single chromosome (2n+1). It causes conditions like Down Syndrome (trisomy of 21st chromosome), Patau syndrome (13th), and Edwards syndrome (18th). Chromosomal aberrations can lead to a wide range of health issues and genetic disorders. Early detection and counseling can help manage these conditions better.