Sex with Other Early Species Might Have Been Secret of Homo sapiens Success Just a few tens of thousands of years ago, Homo sapiens existed next to several close evolutionary cousins, including Neanderthals and Homo floresiensis. But shortly after our human species migrated out of Africa, we were left as the only hominin species on Earth. What was the secret to our success? Did we out-compete the others for resources? Did we just flat-out kill them? Did we reproduce faster? All of those theories have some merit, but thanks to DNA analysis of ancient human and Neanderthal genomes, a new idea is emerging: We may have interbred our way to the top. By analyzing how much of our genomes (nuclear and mitochondrial) we share with these other species, it appears that there was significant “genetic mixing”, if you know what I mean. Many of these hybrid gene mixes could have added new tools for our early immune system, leading to tougher, more survivable humans. We still lack many details in this story, and lots of questions remain. But it’s pretty clear that human evolution does not follow a single line out of Africa. Instead, it’s a web that stretches first across Europe and then into Asia, mixing and branching along the way into the global population that today we see mixing in entirely new ways. Check out the wonderfully detailed full story by Michael Hammer at Scientific American.
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Sex with Other Early Species Might Have Been Secret of Homo sapiens Success

Just a few tens of thousands of years ago, Homo sapiens existed next to several close evolutionary cousins, including Neanderthals and Homo floresiensis. But shortly after our human species migrated out of Africa, we were left as the only hominin species on Earth.

What was the secret to our success? Did we out-compete the others for resources? Did we just flat-out kill them? Did we reproduce faster? All of those theories have some merit, but thanks to DNA analysis of ancient human and Neanderthal genomes, a new idea is emerging: We may have interbred our way to the top.

By analyzing how much of our genomes (nuclear and mitochondrial) we share with these other species, it appears that there was significant “genetic mixing”, if you know what I mean. Many of these hybrid gene mixes could have added new tools for our early immune system, leading to tougher, more survivable humans.

We still lack many details in this story, and lots of questions remain. But it’s pretty clear that human evolution does not follow a single line out of Africa. Instead, it’s a web that stretches first across Europe and then into Asia, mixing and branching along the way into the global population that today we see mixing in entirely new ways.

Check out the wonderfully detailed full story by Michael Hammer at Scientific American.

Source: scientificamerican.com

In ants and bees, there are no sex chromosomes. Instead, sex is determined by whether or not an egg was fertilized. If the egg isn’t fertilized, the offspring is male. If the egg is fertilized, it’s female. So male ants have no fathers, and they have half as many chromosomes as females. Poor little things.

Beatrice the Biologist: Clarification, Sex Determination, and Cheesecake

(via chopdawg)

I’ve always maintained that its not the number of chromosomes that matters, but rather how you use them.

(via blamoscience)

Source: beatricebiologist.com

We Were All Female

AsapSCIENCE brings us an important lesson on human developmental biology. All men - yes, even the manliest of men *cough* - began as females. Sort of.

See, the default developmental pathway for a zygote is toward female. That’s due to signals that come from genes on the X chromosome. In XY males, however, a special Y-chromosome gene inhibits just a few of those X chromosome genes and tunes the embryo to respond to testosterone. This takes what would become female parts and “adjusts” them slightly to become the second male brain.

Yep … your family jewels used to belong to the princess. This also answers the “why men have nipples” question.

On a weird science side note, when this system malfunctions in development, the results can be pretty interesting. In a condition called androgen insensitivity syndrome, the embryo is XY, but can’t respond to those early testosterone signals. Instead, it follows the “default” pathway and develops all of the outer female anatomy (vagina, etc.) but none of the inner (ovaries, uterus). Male, but female!

Source: youtube.com

Most of Nature Thinks Your Sex Life Is Boring

The animal kingdom is full of weird sex. From detachable penises and exploding genitals to four-headed phalluses … let’s just say that evolution has provided life with a variety of entertaining ways to create more of itself. And behind each of those odd adaptations is real biology.

Wild Sex, a new web show coming up from Carin Bondar (who is awesome, btw), will explore all of that. Looks like it’ll be quite entertaining, hilarious, and educational. I’ll definitely be tuning in. Check it out here.

(via io9)

Source: io9.com

Virgin Births Seen in Wild Vipers Parthenogenesis, a form of asexual reproduction where embryos pop up without fertilization from a male, is actually not uncommon in vertebrates. Certain lizard species reproduce exclusively this way. But seeing an organism that usually reproduces sexually adapt this ability out of nowhere? That had never been confirmed … until now. American copperhead and cottonmouth snakes, both common poisonous viper species, were recently observed by NC State researchers reproducing in precisely this way. Females birthed young whose DNA showed no input from a male snake. Many of these pregnancies can involve developmental defects, since it isn’t their biologically “preferred” way to reproduce, but it shows that if certain organisms are faced with the choice of adapting or dying … well, life finds a way. Also be sure to check out this TED Ed video about sex determination throughout the animal kingdom. It’s a strange business. (more at Nature News)
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Virgin Births Seen in Wild Vipers

Parthenogenesis, a form of asexual reproduction where embryos pop up without fertilization from a male, is actually not uncommon in vertebrates. Certain lizard species reproduce exclusively this way. But seeing an organism that usually reproduces sexually adapt this ability out of nowhere? That had never been confirmed … until now.

American copperhead and cottonmouth snakes, both common poisonous viper species, were recently observed by NC State researchers reproducing in precisely this way. Females birthed young whose DNA showed no input from a male snake. Many of these pregnancies can involve developmental defects, since it isn’t their biologically “preferred” way to reproduce, but it shows that if certain organisms are faced with the choice of adapting or dying … well, life finds a way.

Also be sure to check out this TED Ed video about sex determination throughout the animal kingdom. It’s a strange business.

(more at Nature News)

Source: nature.com

Chimps, Bonobos and Us Closest living relative of Homo sapiens? Easy. Chimpanzees, right? It might not be that simple. With the recent sequencing of the bonobo genome, the distinction between the two species is getting fuzzier, as is the question of who’s a closer relative of humans. Bonobos are a small population of chimpanzee-like apes that live in a tiny pocket of the Congo. They themselves split off of the lineage of chimpanzees less than two million years ago after their population was cut off by the Congo river. Unlike the rather aggressive chimpanzees, who are far more widespread across Africa, bonobos are … well, rather less so. Bonobos look so much like chimps (the bonobo is on the right up above) that their behavior is one of the few ways to tell them apart. They are known to settle disputes through sex, the gender combination not always important, with the activity even completed while eating. Sex is their cultural currency. Don’t believe me? Watch this. Chimps do no such thing, to their own recreational detriment. The sequenced bonobo genome only differs from the chimpanzee genome by 0.4% at the DNA level. That’s within the normal variability of chimp genomes! So are they bonobos or are they chimps? How much of species separation is genetic and how much is behavioral? What, if anything in the small genetic difference leads to those huge behavioral changes? And if they are both so closely related, who is our actual closest relative? This is a debate that will continue. (via Ars Technica)
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Chimps, Bonobos and Us Closest living relative of Homo sapiens? Easy. Chimpanzees, right? It might not be that simple. With the recent sequencing of the bonobo genome, the distinction between the two species is getting fuzzier, as is the question of who’s a closer relative of humans. Bonobos are a small population of chimpanzee-like apes that live in a tiny pocket of the Congo. They themselves split off of the lineage of chimpanzees less than two million years ago after their population was cut off by the Congo river. Unlike the rather aggressive chimpanzees, who are far more widespread across Africa, bonobos are … well, rather less so. Bonobos look so much like chimps (the bonobo is on the right up above) that their behavior is one of the few ways to tell them apart. They are known to settle disputes through sex, the gender combination not always important, with the activity even completed while eating. Sex is their cultural currency. Don’t believe me? Watch this. Chimps do no such thing, to their own recreational detriment. The sequenced bonobo genome only differs from the chimpanzee genome by 0.4% at the DNA level. That’s within the normal variability of chimp genomes! So are they bonobos or are they chimps? How much of species separation is genetic and how much is behavioral? What, if anything in the small genetic difference leads to those huge behavioral changes? And if they are both so closely related, who is our actual closest relative? This is a debate that will continue. (via Ars Technica)
Zoom Info

Chimps, Bonobos and Us

Closest living relative of Homo sapiens? Easy. Chimpanzees, right? It might not be that simple. With the recent sequencing of the bonobo genome, the distinction between the two species is getting fuzzier, as is the question of who’s a closer relative of humans.

Bonobos are a small population of chimpanzee-like apes that live in a tiny pocket of the Congo. They themselves split off of the lineage of chimpanzees less than two million years ago after their population was cut off by the Congo river. Unlike the rather aggressive chimpanzees, who are far more widespread across Africa, bonobos are … well, rather less so.

Bonobos look so much like chimps (the bonobo is on the right up above) that their behavior is one of the few ways to tell them apart. They are known to settle disputes through sex, the gender combination not always important, with the activity even completed while eating. Sex is their cultural currency. Don’t believe me? Watch this.

Chimps do no such thing, to their own recreational detriment.

The sequenced bonobo genome only differs from the chimpanzee genome by 0.4% at the DNA level. That’s within the normal variability of chimp genomes! So are they bonobos or are they chimps? How much of species separation is genetic and how much is behavioral? What, if anything in the small genetic difference leads to those huge behavioral changes? And if they are both so closely related, who is our actual closest relative? This is a debate that will continue.

(via Ars Technica)

Secret, Censored 100-Year-Old Manuscript Reveals Penguins’ Deviant Sex Lives Today we scientists argue about things like whether or not it’s acceptable to publish papers detailing the evolution of dangerous influenza strains in laboratories. You know, concerns about bioterrorism, future of the free world, massive pandemics, all that jazz (even though the recent flu research was nowhere near that bad). But if it’s 1915 and you’re studying the mating behaviors of the Adélie penguin, you’re more concerned whether the deviant little birds are too racy for publication in a scientific journal. These little guys may be the cutest of all penguin species, with their squatty frames and adorable little eyes. But as Antarctic zoologist George Levick found out, they also have some pretty odd sex lives. His writings were deemed too racy for publication nearly 100 years ago, but were recently unearthed in the Natural History Museum at Tring. They were finally published this week, but it seems he knew at the time that he was observing the avian version of Eyes Wide Shut, formal wear and all. A page from his notebook is reprinted above, featuring one of many passages coded in the Greek alphabet (lest any women glance upon his notes and besmirch their honor). What does it say? Look away if you possess a delicate constitution (although it’s not Fifty Shades of Grey or anything):  This afternoon I saw a most extraordinary site [sic]. A Penguin was actually engaged in sodomy upon the body of a dead white throated bird of its own species. The act occurred a full minute, the position taken up by the cock differing in no respect from that of ordinary copulation, and the whole act was gone through down to the final depression of the cloaca It’s actually full of interesting biology questions, like why males of a species would copulate without reproduction (something that we do all the time, but normally not seen in animals). But the social pressures of the time banished these observations to dusty boxes for nearly a century.  Previously: Speaking of people in Antarctica studying shocking, simply shocking things I tell you, check out the trailer for the new film about research at the South Pole, Antarctica: A Year On Ice (featuring those kinky little Adélies, yet again) (via Discoblog)
Pop-upView Separately

Secret, Censored 100-Year-Old Manuscript Reveals Penguins’ Deviant Sex Lives

Today we scientists argue about things like whether or not it’s acceptable to publish papers detailing the evolution of dangerous influenza strains in laboratories. You know, concerns about bioterrorism, future of the free world, massive pandemics, all that jazz (even though the recent flu research was nowhere near that bad). But if it’s 1915 and you’re studying the mating behaviors of the Adélie penguin, you’re more concerned whether the deviant little birds are too racy for publication in a scientific journal.

These little guys may be the cutest of all penguin species, with their squatty frames and adorable little eyes. But as Antarctic zoologist George Levick found out, they also have some pretty odd sex lives. His writings were deemed too racy for publication nearly 100 years ago, but were recently unearthed in the Natural History Museum at Tring.

They were finally published this week, but it seems he knew at the time that he was observing the avian version of Eyes Wide Shut, formal wear and all. A page from his notebook is reprinted above, featuring one of many passages coded in the Greek alphabet (lest any women glance upon his notes and besmirch their honor).

What does it say? Look away if you possess a delicate constitution (although it’s not Fifty Shades of Grey or anything): 

This afternoon I saw a most extraordinary site [sic]. A Penguin was actually engaged in sodomy upon the body of a dead white throated bird of its own species. The act occurred a full minute, the position taken up by the cock differing in no respect from that of ordinary copulation, and the whole act was gone through down to the final depression of the cloaca

It’s actually full of interesting biology questions, like why males of a species would copulate without reproduction (something that we do all the time, but normally not seen in animals). But the social pressures of the time banished these observations to dusty boxes for nearly a century. 

Previously: Speaking of people in Antarctica studying shocking, simply shocking things I tell you, check out the trailer for the new film about research at the South Pole, Antarctica: A Year On Ice (featuring those kinky little Adélies, yet again)

(via Discoblog)

Source: blogs.discovermagazine.com