Editorial 1: Scientists finally finish sequencing ‘weird’ male Y chromosome
Introduction
- The Y chromosome is a never-ending source of fascination (particularly to men) because it bears genes that determine maleness and make sperm. It’s also small and seriously weird; it carries few genes and is full of junk DNA that makes it horrendous to sequence.
Making baby boys
- We have known for about 60 years that specialised chromosomes-determine birth sex in humans and other mammals.
- Females have a pair of X chromosomes, whereas males have a single X and a much smaller Y chromosome.
- The Y chromosome is male-determining because it bears a gene called SRY, which directs the development of a ridge of cells into a testis in the embryo.
- The embryonic testes make male hormones, and these hormones direct the development of male features in a baby boy.
- Without a Y chromosome and a SRY gene, the same ridge of cells develops into an ovary in XX embryos. Female hormones then direct the development of female features in the baby girl.
A DNA junkyard
- The Y chromosome is very different from X and the 22 other chromosomes of the human genome.
- It is smaller and bears few genes (only 27 compared to about 1,000 on the X).
- These include SRY, a few genes required to make sperm, and several genes that seem to be critical for life – many of which have partners on the X.
- Many Y genes (including the sperm genes RBMY and DAZ) are present in multiple copies.
- Some occur in weird loops in which the sequence is inverted and genetic accidents that duplicate or delete genes are common.
- The Y also has a lot of DNA sequences that don’t seem to contribute to traits.
- This “junk DNA” is comprised of highly repetitive sequences that derive from bits and pieces of old viruses, dead genes and very simple runs of a few bases repeated over and over.
- This last DNA class occupies big chunks of the Y that literally glow in the dark; you can see it down the microscope because it preferentially binds fluorescent dyes.
Y chromosome is weird!
- We have a lot of evidence that 150 million years ago the X and Y were just a pair of ordinary chromosomes (they still are in birds and platypuses).
- There were two copies – one from each parent – as there are for all chromosomes.
- Then SRY evolved (from an ancient gene with another function) on one of these two chromosomes, defining a new proto-Y.
- This proto-Y was forever confined to a testis, by definition, and subject to a barrage of mutations as a result of a lot of cell division and little repair.
- The proto-Y degenerated fast, losing about 10 active genes per million years, reducing the number from its original 1,000 to just 27.
- A small “pseudoautosomal” region at one end retains its original form and is identical to its erstwhile partner, the X.
- There has been great debate about whether this degradation continues, because at this rate the whole human Y would disappear in a few million years (as it already has in some rodents).
Spoiler alert
- The Y turns out to be just as weird as we expected from decades of gene mapping and the previous sequencing.
- A few new genes have been discovered, but these are extra copies of genes that were already known to exist in multiple copies.
- The border of the pseudoautosomal region (which is shared with the X) has been pushed a bit further toward the tip of the Y chromosome.
- We now know the structure of the centromere (a region of the chromosome that pulls copies apart when the cell divides), and have a complete readout of the complex mixture of repetitive sequences in the fluorescent end of the Y.
Conclusion
- The most important outcome is how useful the findings will be for scientists all over the world. It’s a new era for the poor old Y.
Editorial 2: The Election Commission — autonomy in the crosshairs
Context
- Of late, the Election Commission of India (ECI) has been a focal point of differences between the government and the judiciary. This time, the clash of opinions is over its appointment.
Recent judgment
- The Supreme Court of India, in a judgment, directed that the Chief Election Commissioner (CEC) and the Election Commissioners (EC) will be appointed by the President of India based on the advice of a committee made up of the Prime Minister, the Leader of the Opposition in the Lok Sabha or the leader of the single largest Opposition party and the Chief Justice of India (CJI).
- This judgment of the Constitution Bench was a major step towards broad basing the ECI and enhancing its constitutional status.
- Article 324 of the Constitution contains a provision for such a law to be enacted by Parliament.
The significance
- The significance of this judgment also lies in the fact that this was a unanimous judgment of a five-judge Bench.
- So far, the top officers of the ECI have been appointed by the President of India on the advice of the central government.
- The Bill seeks to replace the Chief Justice of India from the high-powered selection committee, meaning the committee will be made up of the Prime Minister (Chairperson), Leader of the Opposition in the Lok Sabha (Member) and a Union Cabinet Minister to be nominated by the Prime Minister (Member).
- Experience and research show that incumbent governments, especially those with authoritarian streaks, do not usually do away with democratic institutions but, instead, relentlessly work towards making them pliant.
- The institutional structures remain but are drained of their substance. And, in this case, one is dealing with a matter of electoral winnability and a consolidation of state power.
An issue that has seen much debate
- The procedure of appointments of the CEC and the ECs has seen much debate in policy and political circles ever since the Constituent Assembly debates and much has been written about it.
- A suggestion during the Constituent Assembly Debates was that the appointment of the CEC should be subject to confirmation by two-thirds majority in a joint session of both Houses of Parliament (Constituent Assembly debates, June 15, 1949). However, Parliament was entrusted with the charge of making appropriate laws on the matter.
- The V.M. Tarkunde Committee appointed by Jayaprakash Narayan in 1975, the Dinesh Goswami Committee on electoral reforms set up by the then Prime Minister, V.P. Singh, in the 1990s, and the second Administrative Reforms Commission in its fourth report in 2009 among others made recommendations that the appointments of members of the ECI should be more broad based (through a collegium) than leaving this solely to the government on whose advice the President made these appointments.
Held in high regard
- The ECI has been held to be a reliable, responsible and trustworthy institution by the people of India.
- Handling elections that involve about 900 million voters (2019 election data) through a machinery of 11 million personnel in a setting of economic hardship and inequalities is a remarkable feat.
- However, going soft on the ruling party or its ideology, as the perception is, whether this has to do with election schedules, electoral speeches, alleged hateful propaganda, electoral rolls or other kinds of malpractices, is eroding not only its own autonomy but also people’s trust.
Conclusion
- Nevertheless, the point remains that the present regime still sees the ECI as an institution with autonomy. And this autonomy does not gel with its goals. It would instead like a firmer grip on the ECI through statutory means.
