True about mitochondrial inheritance
Ans. b (An offspring bom to an affected female will be affected) (Ref. Nelson paediatrics, Ch. 80. p. 496)Mitochondrial Inheritance# An individual's mitochondrial genome is entirely derived from the mother. Sperm contain few mitochondria, most of which are shed upon fertilization.# Mitochondrial disorders exhibit maternal inheritance; a woman with a mitochondrial genetic disorder will have only affected offspring of either sex, while an affected father will have no affected offspring.# Common manifestations include developmental delay, seizures, cardiac dysfunction, i strength and tone, as well as hearing and vision problems.# Examples include- NARP- MELAS (myopathy, encephalopathy, lactic acidosis, and strokelike episodes),- MERRF (myoclonic epilepsy associated with ragged red fibers),- Kearns-Sayre syndrome (ophthalmoplegia, pigmentary retinopathy, and cardiomyopathy).# Cells may contain a mixture of mutant and normal mitochondria, referred to as heteroplasmy.