The Y chromosome has been notoriously difficult to sequence due to repetitive elements. Junk, right?
Now, researchers from the University of Rochester have found a way to sequence a large portion of the Y chromosome in the fruit fly Drosophila melanogaster—the most that the Y chromosome has been assembled in fruit flies. The research, published in the journal GENETICS, provides new insights into the processes that shape the Y chromosome, “and adds to the evidence that, far from a genetic wasteland, Y chromosomes are highly dynamic and have mechanisms to acquire and maintain genes,” says Amanda Larracuente, an assistant professor of biology at Rochester.
Using sequence data generated by new technology that reads long strands of individual DNA molecules, Chang and Larracuente developed a strategy to assemble a large part of the Y chromosome and other repeat-dense regions. By assembling a large portion of the Y chromosome, they discovered that the Y chromosome has a lot of duplicated sequences, where genes are present in multiple copies. They also discovered that although the Y chromosome does not experience crossing over, it undergoes a different type of recombination called gene conversion. While crossing over involves the shuffle and exchange of genes between two different chromosomes, gene conversion is not reciprocal, Larracuente says. “You don’t have two chromosomes that exchange material, you have one chromosome that donates its sequence to the other part of the chromosome” and the sequences become identical.
The Y chromosome has therefore found a way to maintain its genes via a process different from crossing over, Larracuente says. “We usually think of the Y chromosome as a really harsh environment for a gene to survive in, yet these genes manage to get expressed and carry out their functions that are important for male fertility. This rampant gene conversion that we’re seeing is one way that we think genes might be able to survive on Y chromosomes.” Newscenter, “Male Y chromosomes not ‘genetic wastelands’” at
University of Rochester
Should someone offer a reward for absolutely genuine junk DNA, the DNA equivalent of three metric tons of unrecyclable discarded gum wrappers?:
See also: Humans may have only 19,000 coding genes
“Junk DNA” regulates regeneration of tissues and organs
Note: One junk DNA defender just isn’t doing politeness anymore. Hmmm. In a less Darwinian science workplace, that could become more a problem for him than for his colleagues.
Junk DNA can actually change genitalia. Junk DNA played the same role in defending Darwinian evolution as claims that Neanderthal man was a subhuman. did: The vast library of junk genes and the missing link made Darwin’s story understandable to the average person and the missing link even became part of popular culture. With Darwinism so entrenched, the fact that these beliefs are not based on fact will be difficult to root out of the culture. Darwin-only school systems are part of the problem.
Been a while since we’ve heard much about humans as the 98% or 99% chimpanzee. If the human genome is this fuzzy how would we know? And doubtless, things have gotten more complex.
At Quanta: Cells need almost all of their genes, even the “junk DNA”
“Junk” RNA helps regulate metabolism
Junk DNA defender just isn’t doing politeness any more.
Anyone remember ENCODE? Not much junk DNA? Still not much. (Paper is open access.)
Yes, Darwin’s followers did use junk DNA as an argument for their position.
Another response to Darwin’s followers’ attack on the “not-much-junk-DNA” ENCODE findings
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