The ‘Mother’s Curse’ in Canada

The idea for the mother’s curse goes like this. Most human genes are on chromosomes, but a tiny number are in mitochondria, little power factories in human cells that for reasons of evolutionary history have their own loops of DNA. Sperm do not pass on any mitochondria, but eggs do. Therefore, all sons and daughters inherit their mitochondrial DNA from their mother (great mother’s day present idea: sequence yourmitochondria, make into cool figure, give it to your mom thanking her for the DNA). If a harmful mutation in mitochondrial DNA ends up in a woman, she will be less evolutionarily “fit” and thus less able to pass it along. But if the mutation ends up in a man, nothing happens. He never passes along mitochondrial DNA anyway.

However, this hasn’t been tested all that often in humans. Until a perfect system arose. You see,  the first King’s Daughters—or filles du roi—arrived in New France in 1663, and 800 more would follow over the next decade. They were poor and usually of common birth, but their passage and dowry were indeed paid by King Louis XIV for the purpose of empire building: These women were to marry male colonists and have many children, thus strengthening France’s hold on North America. And so they did.

One of these is Leber’s hereditary optic neuropathy, which causes vision loss, usually in young men. Recently, geneticists using French Canadian genealogy have reexamined the effects of Leber’s and found a striking pattern of inheritance: It seems to show a long-theorized but never-seen-in-humans pattern called the “mother’s curse.”

Want to know more? Read about it here.

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Sperm packages of ungodly size, genitals that double as a souped-up stomach, and an unexpected set of chewing jaws

And all of those are found in just one species, the Pieris rapaethe cabbage white butterfly.

In an wonderful piece over at the Atlantic, we learn about the crazy sex life/organs of this very common butterfly.

I was enthralled reading the whole thing, but the main investigator is quoted below, is really why I’m sharing this.

“Jumping spiders with telescope eyes are singing and dancing to impress their mates. That butterfly on your kale has a chewing jaw in its reproductive tract that helps it to regain control over its own reproductive timing. It is this ability of life to continually surprise us that brings me such joy as a scientist. And it’s my hope that, in some small way, my work can return some childlike wonder to the daily lives of others. It is only through falling back in love with nature that we stand any chance of saving it.” –Nathan Morehouse

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Genitals are the fastest-evolving organs in the animal kingdom. Here’s why:

Genitals are weirdly shaped, which is strange. They only really NEED to be a pipette like device to inject sperm into a cup like device. But what we see in nature is way more complicated and bizarre. The reason? “They’re the result of a furious evolutionary tango of sex, that has been going on of millions of years.” Check out this cool video from TED-Ed to marvel at how odd genitalia are:

Junk science

Mating Ladybirds

Birds do it, beetles do it … (Flickr: Henry Burrows)

Last spring, the journal Current Biology published a report describing something new under the entomological sun: A genus of tiny cave-dwelling insects, dubbed Neotrogla, in which females, not males, have penises.

Or, rather, the females have a thing that they stick inside the males. Once it’s in there, that thing inflates and latches into the male with tiny barbs, binding the couple together in a copulation lasting two to three days, while the thing collects a packet containing sperm and a whole lot of (potentially) nutritious protein. What to call the females’ thing seems to have puzzled even the scientists who described it. In the text of their paper, they call it a gynosome (literally, a “female body”); but in the title, it’s a “female penis.”

This synonymy went from confusing to controversial the moment it hit the popular science press, which almost uniformly chose to go penis-first. “Female insect uses spiky penis to take charge” read the headline in the prestigious journal Nature. “Meet the female insect with giant PENIS whose steamy sex sessions last 70 HOURS,” said the Daily Mirror, caps-locked emphasis sic. Most of the stories, even the Mirror’s, got around to using the word “gynosome” eventually, and many went into more detail about how the organ in question wasn’t really a penis as we know it. LiveScience noted it was “a complex organ composed of muscles, ducts, membranes and spikes,” before adding that its size, relative to the body of a Neotrogla female, was “the equivalent of a man who is 5 feet 9 inches (1.75 meters) tall having a penis about 9.8 inches (24.9 centimeters) long.”

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Sex chromosomes in conflict

House mouse (by Wenfei Tong http://darwinsjackal.blogspot.com/)

House mouse (by Wenfei Tong)

Have you thought that not all the genes in your body might have the same evolutionary interests? The mouse Y chromosome has just been revealed after years of superhuman slog and turns out to be strikingly different from other non-recombining sex chromosomes in two main ways. Firstly, the mouse Y contains almost no DNA signatures of its past as a non sex chromosome. Secondly, most of it isn’t “junk”. Both these observations have shown just how much conflict within a genome can shape the evolution of entire chromosomes.

Figure from Sho et a. 2014, showing how much of the mouse Y contains recently evolved, repetitive coding sequences.

Figure from Sho et a. 2014, showing how much of the mouse Y contains recently evolved, repetitive coding sequences.

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Carnival of Evolution, March 2013

Carnival of Venice 2010

Welcome, readers, to the 57th Carnival of Evolution. This past month, the 204th birthday of Charles Darwin just happened to fall on Mardi Gras, a celebration of life’s exuberant excesses. So put on your most dazzling mask, and join us for an exploration of the endless forms most beautiful to be found in the living, evolving world.

Evolutionary science

In addition to Darwin Day and Mardi Gras, February is the month of Valentine’s Day. So it’s maybe appropriate that evolutionary bloggers had sex on the brain. Joachim describes new research on the specific forms of natural selection that might have supported the evolution of sexual reproduction. Right here at Nothing in Biology Makes Sense!, Amy Dapper writes about one consequence of sex, among grass gobies: “sneaker” males with specialized sperm. And Jeremy Yoder (yours truly) takes a look at daisies that attract pollinators by fooling them into mating with deceptive flower petals.

Meanwhile, Hannah Waters explains why sociable weaver birds nest together—because it pays to stay home and help their parents.

While most songbird species breed before they even turn a year old, sociable weavers rarely breed before the age of two. Instead, these younger birds help raise other nestlings–their siblings as well as unrelated chicks–by gathering food and maintaining the nest’s fluffy interior chambers and external sticks and grass.

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Where have all the ‘N-mt’s gone?

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This week I would like to highlight a recent scientific publication by one of our very own contributor’s here at Nothing in Biology Makes Sense! – Devin Drown. Drown and colleagues recently published an article in Genome Biology and Evolution that investigates how nuclear genes that interact with the mitochondria (N-mt genes) are distributed within the genome. They show that when it comes to the location of genes within the genome, all is not equal, and suggest that conflict between males and females may influence where our genes are located.

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