BIOCHEMICAL MUTATION/GENETICS

DEPARTMENT OF GENETICS AND PLANT BREEDING, C C S UNIVERSITY MEERUT

1. Department of Genetics and Plant Breeding C C S University Meerut Submitted BY KRISHNA KUMAR VERMA M.Sc.( Ag.) Department of Genetics & Plant Breeding, Chaudhary CHARAN SINGH University, Meerut Submitted to DR. S. s . GAURAV Asso. Professor, Department of Genetics & Plant Breeding, Chaudhary Charan Singh University, Meerut BIO CHEMICAL GENETICS

2. Introduction . Inborn errors of metabolism in man. Phenyketonuriya . Alkaptonuriya . Albinism. Goitrous creatinism . Eye transplantation in drosophila. Bio chemical mutation in neurospora. One gene one enzyme hypothesis.

3. BIO CHEMICAL GENETICS IS A BRANCH OF GENETICS AT A BIOCHEMICAL LEVEL AND IN WHICH THE RELATIONSHIP OF GENE AND THEIR CONTROL OVER THE FUNCTION OF AN ENZYME IS OBSERVED. T he Foundation bio Chemical Genetics was laid by Sir Archibald Edward Garrod in 1902 was english Physician .he studied Gene action in men. G.W,Beadle and E .L. Tatum [both N obel Prize winners in1958] was proposed in 1941 a concept called ONE GENE ONE ENZYME HYPOTHESIS. Beadle and Ephrussi in 1957 studied metabolic pathway for Eye C olour in Drosophila.

4. Autosomal recessive metabolic genetic disorder Mutation in the gene for phenylalanine hydroxylase(PAH). When PAH activity is reduced, phenylalanine accumulates and is converted into phenylpyruvic acid( phenylketone ), which can be detected in the urine . Phenyl nine Phenylpyruvic acid PAH ( After mutation in recessive gene) Tyrosine

5. This disease caused by due to mutation in recessive gene CC. Located on 12th chromosome . PKU is rare – it is estimated to affect 1 in every 10,000 babies.

6. Symptoms Most babies with phenylketonuria appear healthy at birth. If it isn't treated, damage to the brain and nervous system can lead to : 1. Learning disabilities 2. behavioural difficulties 3. Pale skin colour

7. A lso called black urine disease Is an inherited genetic disorder of phenylalanine and tyrosine metabolism. This condition is rare, affecting 1 in 250,000 to 1 million people worldwide. Alkaptonuriya is more common in certain areas of Slovakia (where it has an incidence of about 1 in 19,000 people) and in the Dominican Republic. Mutations in the HGD gene

8. The urine of person suffering from this disease turns black on exposser to air. Arthritis (especially of the spine) that gets worse over time. Darkening of the ear. Dark spots on the white of the eye (sclera) and cornea.

9. Albinism is caused by a genetic lack of melanin Melanin is synthesized from the amino acid tyrosine. Tyrosine's breaks down tyrosine. People with albinism have been passed down a nonfunctional tyrosine's allele, which does not allow them to produce melanin.

10. 3,4 Di hydroxyl Phenylalanine Melanin

11. 1. This disease is characterized by several mental and physical retardation and hypertrophy of THYROID GLAND. 2. IN normal person tyrosine is converted into thyroid hormone are essential for normal human metabolism and responsible for normal physical and mental growth mutation at gene CC .

12. Beadle and Ephrussi (1937) studied metabolic pathway for eye color in Drosophila. The transmitted embryonic eye primordial from one flies to other flies at larval stage and result were analyzed in adult (abdomen). The reciprocal crosses of eye transplanted was done among viz . wild, vermillion and cinnabar . In all cases transmitted eye were developed into wild eye or normal eye. But when cinnabar eye was transplanted into vermilion larva to its abdomen which result cinnabar eye color.

13. Tryptophan (vermilion) v gene Kynurenine (cinnabar) 3-hydroxy Kynurenine Ptrin Ommocromes ( bright red eye) ( brown eye color) wild

14. Beadle and Tatum studied biosynthetic pathway of arginine in Neurospora. They reported that biosynthesis of arginine involves several sequential steps and each step is controlled by specific enzyme. The end product of one biochemical reaction serves as a precursor for the next.

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16. George Beadle and Edward Tatum were among the first to investigate biosynthetic pathways They studied growth variants of the fungus, pink bread mould (Neurospora crass) Their proposal, the one-gene-one enzyme hypothesis came out of their experiments