Rabu, 10 Mei 2017

what does ejaculate look like



sperm cells are the smallest cells producedby the human body, at only 50 micrometers long. but a single sperm cell contains a completecopy of all the data found on 23 chromosomes, which can be hundreds of megabytes of information. even your fancy new microsd card can’t competewith that kind of storage density. and thanks to a study published this weekin the journal cell metabolism, we now know


what does ejaculate look like
what does ejaculate look like, that sperm carries not just genetic information,but epigenetic information as well. your dna contains most of the instructionsfor making you, organized into genes, and all those genes together make up your genome. but even though each cell gets a completecopy of that genome, it only needs to use

certain parts -- and it figures out whichparts based on your epigenetic information. it needs the help, because your dna is anincredibly complex molecule -- and it’s also really, really long. if you stretched out a single molecule ofyour dna? it would be two meters long! so, how do you squeeze a two meter long moleculeinside the nucleus of a cell? you wrap the dna tightly around a long filament of proteincalled histone. coiling the molecule into a spring like that compresses it down. but it also introduces a new problem: yourdna is wrapped so tightly around the histone that your cell can’t access most of yourgenetic information anymore.

so, in addition to histone and dna, you alsohave epigenetic markers. “epigenetic” literally means “aboveyour genes.” and those epigenetic markers sit right on top of your dna. they tell the cell where to coil the dna tighter,and where to let it unspool. unspool the dna, and the cell can read the genes in that location.tighten up the coil, and the genes there won’t be expressed in that cell. it’s part of the reason that, say, a neuronbecomes a neuron, and not a muscle cell -- those cells carry different epigenetic data. the neuron reads the parts of your dna thattell it how to be a neuron, and not the parts

that would tell it how to be a muscle cell. that’s how powerful epigenetic markers canbe -- and they can change based on how you live your life. your weight, diet, stresslevels, and even your moods can alter those markers. we also know that they’re inherited, butfor a long time, geneticists thought that sperm cells were too small to contain boththe genome and the epigenetic information of the donor. and while some studies in the past have suggestedthis might not be the case for mice, there hasn’t been much research into the humanside of things. sperm cells were believed to be inert carriersof dna, so scientists just...never really looked into it.

until now!in this study, a group of researchers from the university of copenhagen were specificallylooking at the differences in the sperm cells between lean and obese men. and what they discovered was that those spermcells not only contained epigenetic markers, but they contained different epigenetic markersdepending on whether the donor was lean or obese. specifically, there were differences at thegene regions associated with appetite control. the team compared sperm cells from 13 leanmen and 10 obese men, and then tracked 6 men who were going through weight-loss surgery,to see how the weight loss affected their sperm.

on average, five thousand changes to spermdna were found between samples from before the surgery and a year after. well, the differences in those sperm cellswere found not in the structure of the dna or in the histones -- they were in a different,related kind of molecule, called small rna. and turns out that small rna can also actas an epigenetic marker, by telling the cell which genes to turn on and off. for decades, scientists believed that rnamolecules only functioned as messenger molecules, carrying information to different parts ofyour cells. then, in 1998, geneticists discovered thatsome rna molecules play a huge role in silencing

your genes. they can prevent genes from beingexpressed -- making them an epigenetic marker. they detect certain groups of instructionsin your dna, and then just clip onto them, so the cell can’t access them. and in the men in the study, they clippedonto different parts of the dna, depending if they were lean or obese. women who want to have a child hear a lotof health recommendations, both before and after they get pregnant: things like maintaina healthy weight, don’t smoke, stay away from alcohol and drugs -- because that couldpotentially affect the health of the child, even before conception occurs.

and at least part of the reason is that thesethings can change epigenetic markers, which then get passed on. but according to the lead author on the study,these results tell us that prospective fathers might want to take care of themselves, too. thanks for watching this episode of scishowspace news, and thanks especially to our patrons on patreon who help make this show possible.if you want to help us keep making episodes like this, just go to www.jual-hajarjahanamcair.com.

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