The story so far: The Department of Biotechnology (DBT) recently said that the exercise to sequence 10,000 Indian human genomes and create a database under the Centre-backed Genome India Project is about two-thirds complete. About 7,000 Indian genomes have already been sequenced of which, 3,000 are available for public access by researchers. 

The proponents of the project say it would enable researchers anywhere in the world to learn about genetic variants unique to the Indian population. Countries including the United Kingdom, China, and the United States have launched similarprogrammes to sequence at least 1,00,000 of their population’s genomes. 

What is genome sequencing?

The human genome is the entire set of deoxyribonucleic acid (DNA)residing in the nucleus of every cell of each human body. It carries the complete genetic information responsible for the development and functioning of the organism. The DNA consists of a double-stranded molecule built up by four bases – adenine (A), cytosine (C), guanine (G) and thymine (T). Every base on one strand pairs with a complementary base on the other strand (A with T and C with G) In all, the genome is made up of approximately 3.05 billion such base pairs. .

While the sequence or order of base pairs is identical in all humans, compared to that of a mouse or another species, there are differences in the genome of every human being that makes them unique. The process of deciphering the order of base pairs, to decode the genetic fingerprint of a human is called genome sequencing.

In 1990, a group of scientists began to work on determining the whole sequence of the human genome under the Human Genome Project. The first results of the complete human genome sequence were given in 2003. However, some percentage of repetitive parts were yet to be sequenced. The Human Genome Project released the latest version of the complete human genome in 2023, with a 0.3% error margin.

Costs of sequencing differ based on the methods employed or the accuracy expected. Since an initial rough draft of the human genome was made available, companies have aimed to reduce the cost of generating a fairly accurate “draft” of any individual genome— it has now fallen to a tenth, or to around $1,000 or less (approximately ₹70,000). 

Genomic sequencing has now evolved to a stage where large sequencers can process thousands of samples simultaneously. There are several approaches to genome sequencing — including whole genome sequencing or next generation sequencing — that have different advantages.

The process of whole-genome sequencing, made possible by the Human Genome Project, now facilitates the reading of a person’s individual genome to identify differences from the average human genome. These differences or mutations can tell us about each human’s susceptibility or future vulnerability to a disease, their reaction or sensitivity to a particular stimulus, and so on.

What are the applications of genome sequencing?

Genome sequencing has been used to evaluate rare disorders, preconditions for disorders, even cancer from the viewpoint of genetics, rather than as diseases of certain organs. Nearly 10,000 diseases — including cystic fibrosis and thalassemia — are known to be the result of a single gene malfunctioning.

In the past decade, it has also been used as a tool for prenatal screening, to investigate whether the foetus has sgenetic disorders or anomalies. The New York Times notes that the Nobel Prize-winning technology crispr, which relies on sequencing, may potentially allow ocientists to repair disease-causing mutations in human genomes. Aiquid biopsies, where a small amount of blood is examined for DNA markers, could help diagnose cancer long before symptoms appear. 

In public health, however, sequencing has been used to read the codes of viruses—one of its first practical usages was in 2014, when a group of scientists from M.I.T and Harvard sequenced samples of Ebola from infected African patients to show how genomic data of viruses could reveal hidden pathways of transmission, which might then be halted, thus slowing or even preventing the infection’s spread. Experts say that as sequencing gets cheaper, every human’s genome may feasibly be sequenced as part of routine health care in the future, to better understand personal molecular biology and health. 

At the population level as well, genomics has several benefits. Advanced analytics and AI could be applied to essential datasets created by collecting genomic profiles across the population, allowing to develop greater understanding of causative factors and potential treatments of diseases. This would be especially relevant for rare genetic diseases, which require large datasets to find statistically important correlations.

How did it help during the pandemic?

In January 2020, at the start of the pandemic,Chinese scientist Yong-Zhen Zhang, sequenced the genome of a novel pathogen causing infections in the city of Wuhan, a New York Times report states. Mr. Zhang then shared it with his virologist friend Edward Holmes in Australia, who published the genomic code online. It was after this that virologists, epidemiologists, and pharmaceutical firms began evaluating the sequence to try and understand how to combat the virus, track the mutating variants and their intensity and spread, and to come up with a vaccine. This information was also used to create diagnostic PCR machines.

To enable an effective COVID-19 pandemic response, researchers kept track of emerging variants and conducting further studies about their transmissibility, immune escape and potential to cause severe disease. Genomic sequencing became one of the first steps in this important process. Here, the purpose of genome sequencing was to understand the role of certain mutations in increasing the virus’s infectivity. Some mutations have also been linked to immune escape, or the virus’s ability to evade antibodies, and this has consequences for vaccines and vaccine makers.

Over the course of the pandemic, the United States and United Kingdom scaled up genomic sequencing, tracked emerging variants and used that evidence for timely actions.

India also put in place a sequencing framework, and the Indian SARS-COV-2 Genomics Consortia (INSACOG), a consortium of labs across the country, was tasked with scanning coronavirus samples from patients and flagging the presence of variants known to have spiked transmission internationally. The bulk of its effort was focussed on identifying international ‘variants of concern’ (VoC) marked out by the World Health Organization as being particularly infectious. Samples from international travellers who arrived in India and tested positive were sent to INSACOG for determining the genomic variant.

As of early December 2021, the INSACOG had sequenced about 1,00,000 samples. It was also tasked with checking whether certain combinations of mutations were becoming more widespread in India.

In the later stage of the pandemic, around December 2022, when over 90% of the adult population was already fully vaccinated and over one-fourth of adults boosted, sequencing helped in targeted efforts at ebbing infections. The Health Ministry urged States to ramp up sequencing (and not increase testing) to track new variants as the virus evolved by accumulating mutations. 

What is the significance of the Genome India project?

India’s 1.3 billion-strong population consists of over 4,600 population groups,many of which are endogamous. TThus, the Indian population harbours distinct variations, with disease-causing mutations often amplified within some of these groups. Findings from population-based or disease-based human genetics research from other populations of the world cannot be extrapolated to Indians, says a note from the Indian Institute of Science (IISc). But despite being a large population with diverse ethnic groups, India lacks a comprehensive catalogue of genetic variations.

Creating a database of Indian genomes allows researchers to learn about genetic variants unique to India’s population groups and use that to customise drugs and therapies. About 20 institutions across India are involved in the project, with analysis and coordination done by the Centre for Brain Research at IISc, Bangalore. The Centre’s Department of Biotechnology notes that the project will help “unravel the genetic underpinnings of chronic diseases currently on the rise in India, (for) example, diabetes, hypertension, cardiovascular diseases, neurodegenerative disorders, and cancer”.

By >Daniel Zadik , Leicester University 

The DNA of Albert Perry may change the story of human origins. Perry, an African-American, approached a DNA testing company to find out more about his ancestry. >The results would have come as quite a surprise (had he lived to see them), and have raised questions >for geneticists around the world. 

It turns out that Perry carried a very different type of Y chromosome, never seen before. Every male has a Y chromosome, which is a piece of DNA inherited by sons from their fathers. But, unlike most DNA, the Y chromosome is not shuffled as it is passed down, and changes only slowly through mutation. Tracking these mutations allows scientists to create a genetic tree of fathers and sons going back through time.

As a man may have several sons or none, some branches of the genetic tree die out each generation, while others become more common. Going back through time it is therefore inevitable that all modern Y chromosomes must descend from from one man at some point in the past. He has become known as “Y-chromosomal Adam”.

This Adam was not the first man, or the only man, from his time to contribute to modern human DNA. It is just that, by chance, his Y chromosome was the only one to survive until today.

What is surprising about Perry’s Y chromosome is that it did not descend from Y-chromosomal Adam’s. Or rather that the established “Adam” has lost his title to a new “Adam”, further back in time, where Perry’s branch split from the tree (see figure). While the former-Adam is estimated to have lived around 202,000 years ago, the revised one is thought to be about 338,000 years old.

To find where Perry’s Y chromosome may have come from, samples from around Africa were tested. Several more from Perry’s branch were found amongst the Mbo people of Cameroon.

So can this tell us anything about human origins? Central Africa contains Y chromosomes from both Perry’s branch and the former-Adam’s branch, while the rest of the world has only been shown to contain the former-Adam’s branch (with the exception of Perry himself). This suggests that our revised Adam may have lived in Central Africa.

The oldest-known “modern human” bones are from East Africa. But if Adam lived in Central Africa, does that mean that modern humans could have originated there? Again, it is hard to say. By looking further into the >genetics of modern people , the picture becomes even more complex. 

It so happens that, just like the Y-chromosome is passed down only from father to son, there is a piece of DNA which sits in a different part of the cell called mitochondria, that is passed down only from mother to her children. Tracing back this DNA in a similar way, leads us to a “ >Mitochondrial Eve ”, estimated to have lived about 190,000 years ago. Eve possibly lived in south-eastern Africa. But modern humans have DNA both from Adam and Eve. 

Despite these apparent contradictions, it is possible that modern humans descended from a single localised population, and that geographical differences in diversity today are due to spread and extinction in the intervening years. But it could also be that many of >the genetic and cultural ingredients that produced modern humans existed in different parts of Africa, drifting and spreading until they came together and, by a mixture of luck and natural selection, became the combination that would out-compete their relatives to spread to the rest of the world. 

One way or another, around 200,000 years ago, bones appear that are indistinguishable from today’s. But that is 140,000 years later than the estimated age of the new Adam, leading to the question: was he even “human”?

Answering this is tricky. There was no single moment when we became human, but rather a >gradual process . On an evolutionary timescale, Adam was very recent, and even if he was not “anatomically modern”, he could probably walk down a street today without raising too many eyebrows. 

Given the scarcity of Perry’s branch and the lack of diversity within it, it is also possible that the revised Adam could have been an ancestor of two sub-species (or even species). Could one have become modern humans, while another produced a cousin? What if, long after modern humans had become established and started to spread, they should meet and interbreed? Like all our other close relatives, these cousins eventually disappeared, but maybe they left traces, such as Perry’s Y chromosome, in the modern gene pool.

This may sound shocking, but it would not be unprecedented. When modern humans spread from Africa to Eurasia, they met another cousin, the Neanderthals. Fossils with features from both species have long caused debate, and recently genetic evidence has suggested that today’s non-Africans owe 1 to 4% of their ancestry to >such interbreeding , although no Y chromosomes have yet been identified. 

So, like many discoveries, Perry’s Y chromosome raises more questions than it answers. It will doubtless be fascinating to watch our understanding evolve as the genetics of more individuals, modern and ancient, from more locations are added to the picture.

Daniel Zadik does not work for, consult to, own shares in or receive funding from any company or organisation that would benefit from this article, and has no relevant affiliations. 

This article was originally published at >The Conversation . Read the >original article . 

Published – July 22, 2013 06:37 pm IST

Clarifying the influence of genetic factors that increase the risk of experiencing clinical anxiety may, in the future, help us to identify people who are particularly vulnerable |Image used for representational purpose only
| Photo Credit: DrAfter123

Indonesian President Prabowo Subianto wintesses the 76th Republic Day Parade, at Kartavya Path in New Delhi on Sunday, January 26, 2025
| Photo Credit: ANI

Indonesian President Prabowo Subianto on Saturday (January 25, 2025), at a banquet hosted by President Droupadi Murmu in his honour, spoke about the historical and cultural ties between India and Indonesia, and emphasised the influence of ancient Indian civilization on Indonesian culture, language, and genetics.

President Subianto highlights Indian influence on Indonesian language and genetics sequencing test.

He added, “A few weeks ago I had my genetic sequencing test and my DNA test and they told me that I have Indian DNA. Everybody knows when I hear Indian music, I start dancing.”

President Subianto also lauded Prime Minister Narendra Modi’s leadership and commitment towards alleviating poverty and helping the marginalised while affirming that he himself learnt a lot from him in the few days.

The Indonesian President said he is proud to be in India and further wished “prosperity, peace, and greatness” for the people of India in the coming years.

Mr. Subianto said, “I am very proud to be here (in India)…I am not a professional politician, I am not a good diplomat, I say what is in my heart. I came here for a few days but learned a lot from Prime Minister Modi’s leadership and commitments… His commitment to alleviating poverty, helping the marginalized, and helping the weakest part of your society, is an inspiration for us.”

“I would like to wish the people of India prosperity, peace, and greatness in the coming years. I would like to see Indonesia and India continuing to be close partners and friends,” he added.

Notably, at the invitation of PM Modi, President Subianto paid a State Visit to India from January 23-26. He also attended the celebrations of the 76th Republic Day of India as the Chief Guest. He was accompanied by a high-level delegation including several Ministers as well as Senior Officials of the Indonesian government and a business delegation.

The visit of Indonesian President Prabowo Subianto to Delhi witnessed the signing and renewal of five Memorandums of Understanding on wide-ranging fields, including health, traditional medicine and maritime security.

MoU on Health Cooperation was signed between the Union Ministry of Health and Family Welfare and the Ministry of Health, Indonesia.

The MoU on Maritime Safety and Security Cooperation between the Indian Coast Guard and BAKAMLA, Indonesia was renewed.

Another MoU was signed in the field of Traditional Medicine Quality Assurance between the Pharmacopoeia Commission for Indian Medicine and Homeopathy, which comes under the Ministry of AYUSH and the Indonesian Food and Drug Authority.

After six decades of research, scientists have discovered the gene responsible for the orange fur seen in domestic cats. Two separate research teams found that the characteristic ginger, calico, and tortoiseshell colours in cats are due to a missing piece of DNA in a part of the cat’s genome that doesn’t make proteins. This breakthrough explains why some cats have their distinctive fiery fur.

“The sex-linked orange mutation in domestic cats causes variegated patches of reddish/yellow hair and is a defining signature of random X-inactivation in female tortoiseshell and calico cats. Unlike the situation for most coat colour genes, there is no apparent homolog for sex-linked orange in other mammals,” the authors of the study wrote.

“We show that the sex-linked orange is caused by a 5 kb deletion that leads to ectopic and melanocyte-specific expression of the Rho GTPase Activating Protein 36 (Arhgap36) gene. Single-cell RNA-seq studies from foetal cat skin reveal that red/yellow hair colour is caused by reduced expression of melanogenic genes that are normally activated by the melanocortin 1 receptor (Mc1r)-cyclic adenosine monophosphate (cAMP)-protein kinase A (PKA) pathway, but the Mc1r gene and its ability to stimulate cAMP accumulation are intact.”

“Instead, we show that increased expression of Arhgap36 in melanocytes leads to reduced levels of the PKA catalytic subunit (PKAC); thus, sex-linked orange is genetically and biochemically downstream of Mc1r. Our findings solve a comparative genomic conundrum, provide in vivo evidence for the ability of Arhgap36 to inhibit PKA, and reveal a molecular explanation for a charismatic colour pattern with a rich genetic history.”

“I am fully convinced this is the gene and am happy,” Carolyn Brown, a University of British Columbia geneticist who was not involved in either study, told Science. “It’s a question I’ve always wanted the answer to.”

As per a release, scientists have long been fascinated by tortoiseshell and calico cats: the offspring of a black cat and an orange cat. Multicoloured cats from such a cross are almost always female, suggesting the gene variant that makes fur orange or black is located on the X chromosome. The male offspring of such a cross are typically unicolor because they inherit just one parent’s X chromosome: We can guess, for instance, that Garfield’s mother is orange because he inherited his only X chromosome from her.

Within the last century, researchers’ understanding of genetics has undergone a profound transformation.

Genes, regions of DNA that are largely responsible for our physical characteristics, were considered unchanging under the original model of genetics pioneered by biologist Gregor Mendel in 1865. That is, genes were thought to be largely unaffected by a person’s environment.

The emergence of the field of epigenetics in 1942 shattered this notion.

Epigenetics refers to shifts in gene expression that occur without changes to the DNA sequence. Some epigenetic changes are an aspect of cell function, such as those associated with aging.

However, environmental factors also affect the functions of genes, meaning people’s behaviors affect their genetics. For instance, identical twins develop from a single fertilized egg, and as a result, they share the same genetic makeup. However, as the twins age, their appearances may differ due to distinct environmental exposures. One twin may eat a healthy balanced diet, whereas the other may eat an unhealthy diet, resulting in differences in the expression of their genes that play a role in obesity, helping the former twin have lower body fat percentage.

People don’t have much control over some of these factors, such as air quality. Other factors, though, are more in a person’s control: physical activity, smoking, stress, drug use and exposure to pollution, such as that coming from plastics, pesticides and burning fossil fuels, including car exhaust.

Another factor is nutrition, which has given rise to the subfield of nutritional epigenetics. This discipline is concerned with the notions that “you are what you eat” – and “you are what your grandmother ate.” In short, nutritional epigenetics is the study of how your diet, and the diet of your parents and grandparents, affects your genes. As the dietary choices a person makes today affects the genetics of their future children, epigenetics may provide motivation for making better dietary choices.

Two of us work in the epigenetics field. The other studies how diet and lifestyle choices can help keep people healthy. Our research team is comprised of fathers, so our work in this field only enhances our already intimate familiarity with the transformative power of parenthood.

A story of famine

The roots of nutritional epigenetics research can be traced back to a poignant chapter in history – the Dutch Hunger Winter in the final stages of World War II.

During the Nazi occupation of the Netherlands, the population was forced to live on rations of 400 to 800 kilocalories per day, a far cry from the typical 2,000-kilocalorie diet used as a standard by the Food and Drug Administration. As a result, some 20,000 people died and 4.5 million were malnourished.

Studies found that the famine caused epigentic changes to a gene called IGF2 that is related to growth and development. Those changes suppressed muscle growth in both the children and grandchildren of pregnant women who endured the famine. For these subsequent generations, that suppression led to an increased risk of obesity, heart disease, diabetes and low birth weight.

These findings marked a pivotal moment in epigenetics research – and clearly demonstrated that environmental factors, such as famine, can lead to epigenetic changes in offspring that may have serious implications for their health.

The role of the mother’s diet

Until this groundbreaking work, most researchers believed epigenetic changes couldn’t be passed down from one generation to the next. Rather, researchers thought epigenetic changes could occur with early-life exposures, such as during gestation – a highly vulnerable period of development. So initial nutritional epigenetic research focused on dietary intake during pregnancy.

The findings from the Dutch Hunger Winter were later supported by animal studies, which allow researchers to control how animals are bred, which can help control for background variables. Another advantage for researchers is that the rats and sheep used in these studies reproduce more quickly than people, allowing for faster results. In addition, researchers can fully control animals’ diets throughout their entire lifespan, allowing for specific aspects of diet to be manipulated and examined. Together, these factors allow researchers to better investigate epigenetic changes in animals than in people.

In one study, researchers exposed pregnant female rats to a commonly used fungicide called vinclozolin. In response to this exposure, the first generation born showed decreased ability to produce sperm, leading to increased male infertility. Critically, these effects, like those of the famine, were passed to subsequent generations.

As monumental as these works are for shaping nutritional epigenetics, they neglected other periods of development and completely ignored the role of fathers in the epigenetic legacy of their offspring. However, a more recent study in sheep showed that a paternal diet supplemented with the amino acid methionine given from birth to weaning affected the growth and reproductive traits of the next three generations. Methionine is an essential amino acid involved in DNA methylation, an example of an epigenetic change.

Healthy choices for generations to come

These studies underscore the enduring impact parents’ diets have on their children and grandchildren. They also serve as a powerful motivator for would-be parents and current parents to make more healthy dietary choices, as the dietary choices parents make affect their children’s diets.

Meeting with a nutrition professional, such as a registered dietitian, can provide evidence-based recommendations for making practical dietary changes for individuals and families.

There are still many unknowns about how diet affects and influences our genes. What research is starting to show about nutritional epigenetics is a powerful and compelling reason to consider making lifestyle changes.

There are many things researchers already know about the Western Diet, which is what many Americans eat. A Western Diet is high in saturated fats, sodium and added sugar, but low in fiber; not surprisingly, Western diets are associated with negative health outcomes, such as obesity, type 2 diabetes, cardiovascular disease and some cancers.

A good place to start is to eat more whole, unprocessed foods, particularly fruits, vegetables and whole grains, and fewer processed or convenience foods – that includes fast food, chips, cookies and candy, ready-to-cook meals, frozen pizzas, canned soups and sweetened beverages.

These dietary changes are well known for their health benefits and are described in the 2020-2025 Dietary Guidelines for Americans and by the American Heart Association.

Many people find it difficult to embrace a lifestyle change, particularly when it involves food. Motivation is a key factor for making these changes. Luckily, this is where family and friends can help – they exert a profound influence on lifestyle decisions.

However, on a broader, societal level, food security – meaning people’s ability to access and afford healthy food – should be a critical priority for governments, food producers and distributors, and nonprofit groups. Lack of food security is associated with epigenetic changes that have been linked to negative health outcomes such as diabetes, obesity and depression.

Through relatively simple lifestyle modifications, people can significantly and measurably influence the genes of their children and grandchildren. So when you pass up a bag a chips – and choose fruit or a veggie instead – keep in mind: It’s not just for you, but for the generations to come.

(Authors:Nathaniel Johnson, Assistant Professor of Nutrition and Dietetics, University of North Dakota; Hasan Khatib, Associate Chair and Professor of Genetics and Epigenetics, University of Wisconsin-Madison, and Thomas D. Crenshaw, Professor of Animal and Dairy Sciences, University of Wisconsin-Madison)

(Disclosure Statement:Nathaniel Johnson receives funding from the United States Department of Agriculture and the National Institutes of Health. He has previously received funding through the National Science Foundation, the National Cattlemen’s Beef Association, and the North Dakota Beef Checkoff. Hasan Khatib receives funding no. 2023-67015-39527 from the USDA National Institute of Food and Agriculture. Thomas D Crenshaw receives funding from Hatch Multi-State Research Formula Funds; USDA/Natl. Institute of Food and Agriculture; DHHS, PHS, National Institutes of Health)

This article is republished from The Conversation under a Creative Commons license. Read the original article.
 

(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)

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.

However, new “long-read” sequencing techniques have finally provided a reliable sequence from one end of the Y to the other. The paper describing this Herculean effort has been published in Nature.

The findings provide a solid base to explore how genes for sex and sperm work, how the Y chromosome evolved, and whether – as predicted – it will disappear in a few million years.

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.

Also Read | Men are slowly losing their Y chromosome, but a new sex gene discovery in spiny rats brings hope for humanity

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.

Also Read | The role of the Y chromosome in cancer outcomes studied 

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.

Why the Y is weird

Why is the Y like this? Blame evolution.

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.

Also Read | Male-centric medicine is affecting women’s health 

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).

Sequencing Y was a nightmare

The first draft of the human genome was completed in 1999. Since then, scientists have managed to sequence all the ordinary chromosomes, including the X, with just a few gaps.

They’ve done this using short-read sequencing, which involves chopping the DNA into little bits of a hundred or so bases and reassembling them like a jigsaw.

But it’s only recently that new technology has allowed sequencing of bases along individual long DNA molecules, producing long-reads of thousands of bases. These longer reads are easier to distinguish and can therefore be assembled more easily, handling the confusing repetitions and loops of the Y chromosome.

Also Read | Male fertility crisis: what environmental contaminants have got to do with it 

The Y is the last human chromosome to have been sequenced end-to-end, or T2T (telomere-to-telomere). Even with long-read technology, assembling the DNA bits was often ambiguous, and researchers had to make several attempts at difficult regions – particularly the highly repetitive region.

So what’s new on the Y?

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.

But perhaps the most important outcome is how useful the findings will be for scientists all over the world.

Some groups will now examine the details of Y genes. They will look for sequences that might control how SRY and the sperm genes are expressed, and to see whether genes that have X partners have retained the same functions or evolved new ones.

Others will closely examine the repeated sequences to determine where and how they originated, and why they were amplified. Many groups will also analyse the Y chromosomes of men from different corners of the world to detect signs of degeneration, or recent evolution of function.

It’s a new era for the poor old Y.