Gabfest: And Thereby Hangs A Tail

It didn't strike you that you could have called on my ever-busy hotline fielded by alien minions to coordinate the move smoothly and efficiently. Nah, you grew smug with the three hours edit-window. Ira jab dekhegi to samaj jayegi. She has three lazy hours now. If not a Hebrew hand, atleast a friendly lending hand hi sahi.

(Humph!)

 

You can ask your buddies in the mod crew to help rearrange. I hear you're all connected and whatnot - what with the impressive success in changing the edit window.

 

That was only a subset of the titles that Shah Jahan used!

Often, 'Alam' is used in the wider sense of 'cosmos' or 'universe', while 'Jahan' (as in 'Jahan Panah') is used in the sense of 'world' or 'realm' - although both words may be taken to mean 'universe'.

You know, those people with all those titles probably brought a lot of misery with them - something about absolute power corrupting absolutely - dispelling sorrows, hmmmm, maybe not so much?

 

Few days, I wake up and think to myself, what the heck did I do in my school days. Of course, I had loads of fun but I should have flipped a book once or twice to get the basics right. How can my fundamental understanding of genetics be so awry! During meiosis division of a cell to form an egg or a sperm, I assumed that a pair of chromosomes just splits at the centre and the genetic variation is brought on by an entire random chromosome (allele) inherited in that process.

Mom= {a[gene], b[gene], c[gene]} from her mom or {A[gene], B[gene], C[gene]} from her dad
and Dad= {a'[gene], b'[gene], c'[gene]} from his mom or {A'[gene], B'[gene], C'[gene]} from his dad

Child inherits

{a[gene], b[gene], c[gene]} and {a'[gene], b'[gene], c'[gene]} or
{a[gene], b[gene], c[gene]} and {A'[gene], B'[gene], C'[gene]} or
A[gene], B[gene], C[gene]} and {a'[gene], b'[gene], c'[gene]} or
A[gene], B[gene], C[gene]} and {A'[gene], B'[gene], C'[gene]}

Thus, the dominant and recessive alleles in that combination is creating the outward phenotype. This is just one chromosome. And this happens across 23 pairs. But this is only independent assortment, I didn't know there was some called cross-over/reshuffle explained here

The first is called independent assortment, which refers simply to the fact that each homologous pair of chromosomes is separated into different daughter cells. Thus, the two alleles of any given gene in the parent cell—one on each of the homologous chromosomes—do not maintain any association with each other as meiosis works its way along. Each daughter cell receives a random mixture of maternal and paternal chromosomes, which leads to a huge number of possible combinations. Theoretically, a daughter cell could have 8,400,000 different combinations of chromosomes! But independent assortment is not the only means of creating genetic variation. In the section on prophase I, remember how we discussed the process of crossing over? When homologous chromosomes overlap and trade some of their genetic material, many, many more combinations of alleles are possible in the resulting daughter cells. Crossing over thus contributes to genetic recombination. Crossing over is a very important phenomenon in genetics. When chromosomes overlap, genetic material from one chromosome (inherited from the mother, say) can trade places with genetic material from the other chromosome (inherited from the father). For example, your mother’s brown-eyed allele could switch places with your father’s blue-eyed one. This process shuffles the genetic information, creating chromosomes that are unique combinations of maternal and paternal alleles, and not just copies from one parent or the other.

Child can inherit

{a[gene], B[gene], c[gene]} and {a'[gene], b'[gene], C'[gene]} during cross over.

But this knowledge stumped me. If that was that case, Thomas Hunt Morgan's mutated white-eyed male fly breeding experiment with red-eyed female fly could not have yielded consistent results. At some stage or form, that male-specific white-eyed mutation should have crossed over in females if the genetic material is crossing over which means alleles on Y chromosome can jump to X chromosome in that homologous chromosome. What is preventing that white-eyed mutation from crossing over? Similarly, any sex-linked phenotype (gender: male, or any male-related mutation) could partially be observed if the protein (genotype) encoding that trait (phenotype) is crossing over in females. Why are autosomes different from sex chromosomes and what is preventing that jump? I came across this X-Y crossover.

The pseudoautosomal region behaves similarly to the autosomes during meiosis, allowing for segregation of the sex chromosomes. Just proximal to the pseudoautosomal region on the Y chromosome is the SRY gene (sex-determining region of the Y chromosome), which is critical for the normal development of male reproductive organs. When crossing over extends past the boundary of the pseudoautosomal region and includes this gene, sexual development will most likely be adversely affected. The rare occurrences of chromosomally XX males and XY females are due to such aberrant crossing over, in which the Y chromosome has lost—and the X chromosome has gained—this sex-determining gene.


Question: Based on above study, abnormal reproductive organs could arise due to X-Y crossover, so, theoretically, Morgan's experiment could have yielded a white-eyed female if the Y-specific white-eye gene (in dad) crossed over to X (in dad) and is dominant over the the other inherited X (mom). There is no absolute sex-linked variation if genetic material can cross over from Y to X or X to Y. Am I getting this wrong? Is there a hard barrier to breach beyond that pseudoautosomal region in sex chromosomes?

 

I haven't watched Bahubali. I might, when it is available on Netlix.

I heard it has smashed all box office records. I also heard that it was to be released in China.

I don't understand the fascination of Chinese with Indian films, whereby they are willing to endure three hours of dancethons and singfests to revel in Indian fantasia, nevertheless, we might soon see Bahubali souvenirs and merchandise in Dandong province.

 

Letter from Bach to King Frederick cited in Gödel, Escher, Bach: An Eternal Golden Braid:

MOST GRACIOUS KING!

In deepest humility I dedicate herewith to Your Majesty a musical offering, the noblest part of which derives from Your Majesty's own august hand. With awesome pleasure I still remember the very special Royal grace when, some time ago, during my visit in Potsdam, Your Majesty's Self deigned to play to me a theme for a fugue upon the clavier, and at the same time charged me most graciously to carry it out in Your Majesty's most august presence. To obey Your Majesty's command was my most humble dim. I noticed very soon, however, that, for lack of necessary preparation, the execution of the task did not fare as well as such an excellent theme demanded. I resoled therefore and promptly pledged myself to work out this right Royal theme more fully, and then make it known to the world. This resolve has now been carried out as well as possible, and it has none other than this irreproachable intent, to glorify, if only in a small point, the fame of a monarch whose greatness and power, as in all the sciences of war and peace, so especially in music, everyone must admire and revere. I make bold to add this most humble request: may Your Majesty deign to dignify the present modest labor with a gracious acceptance, and continue to grant Your Majesty's most august Royal grace to

Your Majesty's
most humble and obedient servant

Is that a good enough template for us to adhere to when we write to you Alam-Panah? I have developed earworm for "Your Majesty" on reading it. I wonder what made Bach write such an unctuous letter.

 

Surely you jest? What does your shoe have to do with Our Majesty? Off with his head!

Dude, this was Frederick The Great, back in the day when Prussia was an army with a country; an all round amazing Philosopher king who might have made Plato proud. I'd write him an unctuous letter.

 

Good catch! Bach needs a proof-reading session from Your Alam-Panah. Hold on, what if Bach was playing on the word "resoul". I resouled (replugged into my errant soul)

Flattery cheapens admiration. Comparison though may put things into perspective starkly. Plato, proud of his at several remove pupil, would be concise and straight with Frederick and remark : "You are the real thing! Rest are flickering shadows. Your Ancestor, Plato"