MORE ON GENES -IV

 MORE ON GENES -IV

Speaking of the infallibility of safeguarding chromosome number typical to a species, it is important to indicate that the normal biological systems by virtue of their 2 sets of chromosomes are named diploid; if it gets to be 3x [triploid], 4x [tetraploid] and more than 4x generally called Polyploid. All such ‘enhanced chromosome numbers’ would cause changes or  irreparable genetic damage  because the number would be unusual for the species. For reasons of human greed and experimental studies polyploid plant varieties are generated for higher yield. But they are man-made aberrations. Their reproductive cycles are not reliable.

It is always a simple, straightforward step to handle diploid [2x] →haploid [x] →diploid [2x] again, through the steps mentioned earlier. Carefully keep track of the following information. Of the 46 chromosomes in humans 44 are involved in general physical characteristics and only 2 are determinants of our gender [sex] as male or female. In accordance, these are named sex chromosomes. The chromosome complement in a human expresses itself as Male [X, Y] or as Female [X X]. In other words when 46/ 2 = 23, 22 of them stand for the structure and only 1 remains for sex determination. 22+1 =23[ EGG] and another 22+1= 23 [sperm which may have 22+X or 22+Y as the XY from father can segregate as X +22 or as Y+22]  Please note , being from the mother,  eggs always carry only X; only sperm can carry X or Y .  

When egg [x] fuses with sperm with x → female off spring; if egg[x] fuses with sperm with y→ male off spring.  Strictly mother is no cause for the sex of the off spring.

Look at Nature’s game on chromosome number

Rhesus monkey has diploid number 42 and so the egg or sperm would carry 21 chromosomes.

Gorilla and Orangutan have diploid number 48; so the egg or sperm would carry 24 chromosomes; Where as humans have diploid number 46 ; so, the egg or sperm would carry 23 chromosomes.

Using these numbers my Prof [T.R. Balakrishna ] used to state “the difference in number by just one chromosome in the haploid set makes Man or Monkey”.

It is important to inform our non-biology friends that Nature has managed to ‘design’ the biological apparatus and all its activities placing exceptional priority to the possibilities of likely happenings in future. Therefore, there are additional or superfluous genes in all biological systems. Such genes do not make proteins; but are carried through the species. These are called ‘silent genes’, but can get activated if the exigency arises.

Some American writers dub them as ‘Junk DNA’. But, common sense tells us that nature never carries any junk and we may not be smart enough  to recognize the hidden opportunities thereof. Bio-systems need to be self sufficient especially for their basic machinery. They cannot borrow any material from outside the system boundaries. Just as the traditional Indian grandma keeps stock of several utensils big and large un-used with the lone prospect of their being used on an important occasion, these cells retain unused DNA for DNA repair or correction for defects before all critical genes are lost by deletion or addition of  unwanted bases. That in brief, is the story of Genes -as relevant to our understanding. If my statements are unclear or wrong, please get necessary clarifications instead of curses to the writing.

Prof. K. Raman