The Y chromosome is difficult to decode even with latest sequencing technologies. The question which genes lie on the male sex chromosome and where they came from is therefore hotly debated. Using a new analysis method, scientists from Vetmeduni Vienna have now made a crucial breakthrough. They were able to show that genetic material in fruit flies is often transferred to the Y chromosome from the other chromosomes. Although this transfer largely occurs as a result of “accidents”, they could now demonstrate that some of these transfers create functional genes. The findings, published in PNAS, will supply new momentum for the research of the male chromosome in other species.
Y chromosomes, which are only inherited paternally, evolved from “normal” chromosomes known as autosomes. As males only possess one Y chromosome, there is no counterpart for recombination, the direct exchange of genetic material. This makes the deletion of harmful mutations on the Y chromosome more difficult than in other chromosomes.
As a result, genes on the Y chromosome usually undergo a process of degeneration. Earlier studies with fruit flies have shown that new genes can be transferred onto the Y chromosome, although the rate was estimated as very low (1 transfer in 10 million years).
Researchers from the Institute of Population Genetics at Vetmeduni Vienna, using a new and highly specific analysis method, could now provide fresh momentum to help decode the evolutionary dynamics of the Y chromosome. Their study shows that ten times more new genes are transferred onto the Y chromosome in fruit flies than had been previously thought. Some of these new genes even appear to have taken on important functions.
New method brings momentum to the previously difficult identification of Y-linked genes
The Y chromosome has been a tough nut to crack in genome research. As it possesses only few functional genes, and these are embedded in repetitive DNA that is difficult to analyse, finding these genes is a challenge. “Only seven functional genes have been identified on the Y chromosome of Drosophila melanogaster. But we suspect that the number of functional genes as well as the actual transfer rate must be higher,” says first author Ray Tobler.
“We therefore developed a new analysis method that allows us to efficiently search for gene transfers onto the Y chromosome, so-called GeTYs.”
The researchers’ trick consisted in sequencing the genome of males and females from a so-called inbred strain of fruit flies. These differ only in the Y chromosome sequence. “The key to our results was to search for variants in the males that do not exist among the females,” says Tobler.
“That means we worked without any known Y chromosome sequences that would usually be used for a comparison. This allowed us to trace the transferred genes back to so-called retrocopies, which are created when the RNA transcript of a gene is inserted into the Y chromosome.”
Transferred RNA copies and important selection mechanisms identified for the first time
All previously described gene transfers onto the Y chromosome involved the transfer of a piece of the chromosome and not an RNA transcript. “The high number of validated gene transfers allowed us to statistically show that there were differences between Drosophila species,” explains senior author Christian Schlötterer. “We only found genes originating from an RNA transcript in the closely related D. mauritiana and D. simulans, which suggests that the transfer mechanisms are species-specific.”
New impetus for Y chromosome research in other species
A special surprise for the research team was that four of the 25 newly transferred genes on the Y chromosome have already assumed an important function there. “As these new genes can be found in all individuals of a species, the question arises as to which functions these new Y-linked genes could have,” says Tobler. Until now, it has been still completely unclear if and how long these new genes can withstand the deterioration of the Y chromosome. As the new analysis method does not require a reference genome for the Y chromosome, it offers enormous potential to study the dynamics of new genes on the Y chromosome in many different species. “I expect many more exciting findings,” concludes Christian Schlötterer.
The article “High rate of translocation-based gene birth on the Drosophila Y chromosom“ by Ray Tobler, Viola Nolte and Christian Schlötterer was published in PNAS.
About the University of Veterinary Medicine, Vienna
The University of Veterinary Medicine, Vienna in Austria is one of the leading academic and research institutions in the field of Veterinary Sciences in Europe. About 1,300 employees and 2,300 students work on the campus in the north of Vienna which also houses five university clinics and various research sites. Outside of Vienna the university operates Teaching and Research Farms. The Vetmeduni Vienna plays in the global top league: in 2017, it occupies the excellent place 8 in the world-wide Shanghai University veterinary in the subject "Veterinary Science". http://www.vetmeduni.ac.at
Institute of Population Genetics
University of Veterinary Medicine Vienna (Vetmeduni Vienna)
T +43 1 25077-4300
Science Communication / Corporate Communications
University of Veterinary Medicine Vienna (Vetmeduni Vienna)
T +43 1 25077-1165
Mag.rer.nat. Georg Mair | idw - Informationsdienst Wissenschaft
At last, butterflies get a bigger, better evolutionary tree
16.02.2018 | Florida Museum of Natural History
New treatment strategies for chronic kidney disease from the animal kingdom
16.02.2018 | Veterinärmedizinische Universität Wien
Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale
Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...
For photographers and scientists, lenses are lifesavers. They reflect and refract light, making possible the imaging systems that drive discovery through the microscope and preserve history through cameras.
But today's glass-based lenses are bulky and resist miniaturization. Next-generation technologies, such as ultrathin cameras or tiny microscopes, require...
Scientists from the University of Zurich have succeeded for the first time in tracking individual stem cells and their neuronal progeny over months within the intact adult brain. This study sheds light on how new neurons are produced throughout life.
The generation of new nerve cells was once thought to taper off at the end of embryonic development. However, recent research has shown that the adult brain...
Theoretical physicists propose to use negative interference to control heat flow in quantum devices. Study published in Physical Review Letters
Quantum computer parts are sensitive and need to be cooled to very low temperatures. Their tiny size makes them particularly susceptible to a temperature...
Let’s say the armrest is broken in your vintage car. As things stand, you would need a lot of luck and persistence to find the right spare part. But in the world of Industrie 4.0 and production with batch sizes of one, you can simply scan the armrest and print it out. This is made possible by the first ever 3D scanner capable of working autonomously and in real time. The autonomous scanning system will be on display at the Hannover Messe Preview on February 6 and at the Hannover Messe proper from April 23 to 27, 2018 (Hall 6, Booth A30).
Part of the charm of vintage cars is that they stopped making them long ago, so it is special when you do see one out on the roads. If something breaks or...
15.02.2018 | Event News
13.02.2018 | Event News
12.02.2018 | Event News
16.02.2018 | Information Technology
16.02.2018 | Health and Medicine
16.02.2018 | Physics and Astronomy