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(please answer all, not partially. If you do not know theses all, Please don\'t answer)

1. Some might say that our behaviors are all under our own control, others say that genetics plays a role in our behavior. Explain.

2. Describe polygenic inheritance and give 2 examples in humans.

3. Describe Down syndrome, give symptoms and cause.

Solution

1. Genes do play a necessary role in inheritance of characters from parents to offspring...this is why children share characters similar to their parents than others.,,,but that characters are expressed as behaviour depending upon multiple factors like society, peers, culture , customs, bonding, etc.. so all kids dont behave alike though born to same parents..

2. certain diseases get inherited due to a single gene defect ..i.e. monogenic inheritance ..eg.CFTR(cystic fibrosis transmembrane regulator) mutation on chromosome 7 causes cystic fibrosis..

whereas certain diseases have a polygenic inheritance in which multiple risk factors need to be present for the disease to occur.... eg. essential hypertension, type 2 diabetes mellitus, coronary artery disease..,

therefore children of the parents suffering from these disorders are at relatively higher risk than those born to normal parents,, but can be protected from disease by life style modifications like diet restriction in salt and high glycemic foods,, regular brisk walk for 30min/day,,meditation and yoga..and adopting type b personalities than type a.

3.Down syndrome is a chromosomally mediated genetic disorder which occurs due to TRISOMY 21.

this can occur due to multiple causes but mainly due to nondisjunction of maternal chromosomes during meiosis,..leading to exrtra chromosome.,, other causes include mosaicism,,etc.

increased maternal age >35yrs increases the risk.

can be diagnosed by screening with triple screen test , confirmed with karyotyping.

symptoms- short stature, mental retardation i.e low I.Q., obliquely slanting eyes, simian crease, umblical hernia, low set ears, large tongue, brachycephaly, obesity