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Genetics
The document provides an extensive overview of genetics and its significance in health, including types of genetic disorders such as chromosomal abnormalities, Mendelian disorders, and multifactorial disorders. It discusses essential concepts like genes, alleles, inheritance patterns, and the implications of genetic mutations on human health. Additionally, it covers specific genetic conditions, their incidence, and associated characteristics.
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Genetics
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- 3. Importance • 2300 hereditarydiseases • 25-40% of all cases treated by health services • Explain incidence ,cause and clustering of cases in populations
- 6. GENETICS • Definition: The studyof heredity and its variation. • Endogenous factors of health and disease • Interaction between nature and nature
- 7. THANKS TO….. Gregor J.Mendel Sir Francis Galton Thomas Hunt Morgan Sir Charles Darwin Tjio
- 8. CHROMOSOME Linear strand madeof DNA that carries genetic information
- 9. Human Chromosomes 46 22pairs autosomes 1 pair sex chromosomes
- 10. Grp-A Grp-B Grp-C Grp-D Grp-E Grp-FGrp-G C G 7 Groups
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- 13. Mitosis vs Meiosis •Mitosis is used by single-celled organisms to reproduce; it is also used for the organic growth of tissues, fibers, and membranes. • Meiosis is found in sexual reproduction of organisms, and is further broken down into meiosis I and II.
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- 21. • A geneis the basic unit of heredity, made of DNA and codes for a specific protein • Loci vs Alleles • (Loci A,a,b,b ;Alleles Aa , bb) • Homozygous (bb) vs Heterozygous (Aa) • Dominant (A) vs Recessive (b) A a b b Allele A a Allele b b Genes
- 23. • Genotype vsPhenotype • Ex: ABO blood groups • Polygenes • Ex: Ht ,skin color ,refractive errors • Penetrance: expressivity • Responsible for skip generations
- 24. Mutation: permanentchange in genetic structure Aberrations • Abnormality in the chromosome • Numerical Structural Non-disjunction (Aneuploidy, polyploidy) Translocation Deletion Duplication Inversion Isochromosomes Mosaisicm
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- 35. Gregor Mendel and Laws ofInheritance
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- 37. 1. Chromosomal abnormalities 2.Mendelian disorders 3. Multifactorial disorders 4. Mitochondrial disorders 5. Non-inherited genetic disorders Genetic disorders can be classified as
- 38. Chromosomal disorders a. Sex-chromosomalb. Autosomal •Embryonic & fetal wastage •5.6 per 1000 live births 1.Chromosomal Abnormalities
- 39. a. Related toSex-chromosomes • Klinefelter’s syndrome • XYY syndrome • Turner’s syndrome • Super female
- 40. 1 in 1000males •XXY / XXXY males •Sterile •Gynaecomastia •Mental retardation •Sons of older women XYY syndrome •1 in 1000 males •Over 6ft tall •Aggressive, antisocial behavior Klinefeltor’s syndrome
- 41. Turner’s syndrome • 1in 7500 live born girls • XO female • Infertile • Webbed neck • Coarctation of aorta • Mental retardation Super female •XXX,XXXX,XXXXX female •Mental retardation •Under developed genetalia
- 42. • Down’s syndrome •Patau’s syndrome • Edward’s syndrome. • Etc., b.Related to autosomes
- 43. Down’s syndrome •Syn :Mongolism •Incidence:1 in 900 (Europe) •Defect :Extra chromosome on 21st pair •Trisomy 21 •Common in women conceiving after 40 yrs of age
- 44. •Mentally retarded •Round head,tilted eye slits. Malformed ears •Infections •Congenital heart disease •Acute leukemia •Pleasant –love music C/F
- 45. 2 . Mendeliandisorders • Incidence:1% of all live births • Inherited according to the Mendelian Laws 1,Law of unit characters 2,Law of dominance 3,Law of segregation • Mutations at individual loci Mendelian / single gene disorders a.Autosomal b.Autosomal c.Sex-linked dominant recessive
- 47. a.Autosomal dominant inheritance •An individual with autosomal dominant trait will produce two types of gametes-half with normal alleles and half with mutant gene • Offspring of such individual have 50:50 chance of being affected irrespective of sex (provided other parent is normal)
- 48. • Achondroplasia • Huntington’schorea • Neurofibromatosis • Polyposis coli, familial • Marfan’s syndrome • Retinoblastoma • Etc., Ex :
- 49. Achondroplasia •Mutation in fibroblast growthfactor receptor gene 3 •Shortening of limbs •Large head •Kyphosis/lordosis •Varus/valgus C/F
- 50. 2.Autosomal recessive inheritance •Both parents should be heterozygous • Each offspring of such parents has 1:4 chance of being affected • Occur sporadically in outwardly normal parents
- 51. Ex : • Cysticfibrosis • Phenylketoneuria • Albinism • Tay-sachs disease • Alkaptonuria • Fibrocystic disease of pancreas • Haemoglobinopathies • Etc ,.
- 52. Cystic fibrosis • 2.5to 5 per 1000 live births • Mutant CFTR gene • Affects respiratory system & GIT • Recognized and treated earlier, life expectancy in developed countries is about 30 yrs
- 53. 3.Sex linked inheritance Sexlinked traits a. Recessive sex linked b. Dominant x-linked
- 54. a. Recessive sex-linked •Mutant gene on X-chromosome in males will express readily due to absence of normal allele while in females will not express in presence of normal allele • If affected male marries normal female; all daughters carriers & sons escape • If carrier female marries normal male;daughters-50% carriers,50% normal:sons-50% affected,50% normal
- 55. Ex : •Haemophilia A& B •Duchenne muscular dystrophy •Color blindness •G-6-PD deficiency •Hydrocephalus •Retinitis pigmentosa •Etc.,
- 56. Haemophilia •15-20 per 100,000males born •Absence, decrease or reduced functioning of blood coagulating factors VIII,IX •Hemorrhage ,hemarthrosis •Treatment :blood transfusions, plasma derivatives •Threat :Hepatitis, AIDS European Royalty with hemophiliaExcessive bruising in haemophilia
- 57. Duchenne muscular dystrophy •Decreasedproduction of dystrophin •Waddling gait by 1st decade •Progressive difficulty in walking •Bed ridden •Death •Carrier females alone transmit the disease
- 58. b. Dominant x-linked •Affectedmale transmits the disease to ALL his daughters but none of his sons •Excess of females affected •Ex :Vit D resistant rickets Xg blood group Familial hypophosphatemia
Editor's Notes
- #34 Swapping of genetic material