Is Venus the two-faced cat really a chimera?

Genetics explained, with added kittens.

Venus the cat has been in the news. She has heterochromia – that is, her two eyes are different colours – as well as a perfectly placed black splodge (technical term), which makes her look like Popular Batman Villain Two-Face.

Why is she like that? One possibility is that she is a chimera. This term, taken from the mythical monster with the heads of a goat, lion and snake, refers to a real – albeit relatively rare – condition where two genetically distinct embryos merge in the womb.

A chimera is essentially the reverse of identical twins. In the latter, one fertilised egg splits completely and forms two separate embryos; in the former, two fertilised eggs merge together and grow into one child.

The cells which come from each of the fertilised eggs maintain their own character – so if one egg had genes for black hair and the other for white, the resulting chimera would have mottled black and white fur:

A chimeric rat with her babies. Photograph: Wikimedia commons

The thing is, Venus may not actually be a chimera.: her perfectly split face may just be a fluke placement of an otherwise normal tortoiseshell pattern. National Geographic's Katia Andreassi writes:

Female cats, said Leslie Lyons, a professor at the University of California, Davis, already have two X chromosomes so they can sport that coat without the extra X. That means Venus is not necessarily a chimera.

To find out would require genetic testing, said Lyons. With samples of skin from each side of the cat, "we can do a DNA fingerprint—just like on CSI—and the DNA from one side of the body should be different than the other."

But there is still a mystery about Venus - her single blue eye. Andreassi adds:

Cat eyes are typically green or yellow, not blue. A blue-eyed cat is typically a Siamese or else a cat with "a lot of white on them," she explained.

Venus appears to have only a white patch on her chest, which to Lyons is not enough to explain the blue eye.

Science: making cool cats cooler.

Venus the "chimera" cat.

Alex Hern is a technology reporter for the Guardian. He was formerly staff writer at the New Statesman. You should follow Alex on Twitter.

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Why Twitter is dying, in ten tweets

It's ironic that the most heated discussions of the platform's weaknesses are playing out on the platform itself. 

Twitter has been dying since 2009, and commentators have pre-emptively declared it deceased pretty much every year since. To declare that it's on the downturn has become a bit of a cliché. But that doesn't mean that it isn't also, well, true.

Grumbling among users and commentators has grown to a roar over the past few days, thanks in part to a Buzzfeed report (refuted by Jack Dorsey, Twitter's CEO) claiming the service will move away from a chronological timeline and towards an algorithmic one. Users coined the hashtag #RIPTwitter in response, and, tellingly, many of their complaints spanned beyond the apparently erroneous report. 

They join a clutch of other murmurings, bits of data and suggestions that things are not as they should be in the Twitter aviary. 

Below is one response to the threat of the new timeline, aptly showing that for lots of users, the new feed would have been the straw that broke the tweeters' backs:

Twitter first announced it was considering a new 10,000 character limit in January, but it's yet to be introduced. Reactions so far indicate that no one thinks this is a good idea, as the 140 character limit is so central to Twitter's unique appeal. Other, smaller tweaks – like an edit button – would probably sit much more easily within Twitter's current stable of features, and actually improve user experience: 

While Dorsey completely denied that the change would take place, he then followed up with an ominous suggestion that something would be changing:

"It'll be more real-time than a feed playing out in real time!" probably isn't going to placate users who think the existing feed works just fine. It may be hard to make youself heard on the current timeline, but any kind of wizardry that's going to decide what's "timely" or "live" for you is surely going to discriminate against already alienated users.

I've written before about the common complaint that Twitter is lonely for those with smaller networks. Take this man, who predicts that he'll be even more invisible in Twitter's maelstrom if an algorithm deems him irrelevant: 

What's particularly troubling about Twitter's recent actions is the growing sense that it doesn't "get" its users. This was all but confirmed by a recent string of tweets from Brandon Carpenter, a Twitter employee who tweeted this in response to speculation about new features:

...and then was surprised and shocked when he received abuse from other accounts:

This is particularly ironic because Twitter's approach (or non-approach) to troll accounts and online abusers has made it a target for protest and satire (though last year it did begin to tackle the problem). @TrustySupport, a spoof account, earned hundreds of retweets by mocking Twitter's response to abuse:

Meanwhile, users like Milo Yiannopolous, who regularly incites his followers to abuse and troll individuals (often women and trans people, and most famously as part of G*merg*te), has thrived on Twitter's model and currently enjoys the attentions of almost 160,000 followers. He has boasted about the fact that Twitter could monetise his account to pull itself out of its current financial trough:

The proof of any social media empire's decline, though, is in its number and activity of users. Earlier this month, Business Insider reported that, based on a sample of tweets, tweets per user had fallen by almost 50 per cent since last August. Here's the reporter's tweet about it:

Interestingly, numbers of new users remained roughly the same – which implies not that Twitter can't get new customers, but that it can't keep its current ones engaged and tweeting. 

Most tellingly of all, Twitter has stopped reporting these kinds of numbers publicly, which is why Jim Edwards had to rely on data taken from an API. Another publication followed up Edwards' story with reports that users aren't on the platform enough to generate ad revenue:

The missing piece of the puzzle, and perhaps the one thing keeping Twitter alive, is that its replacement hasn't (yet) surfaced. Commentators obsessed with its declining fortunes still take to Twitter to discuss them, or to share their articles claiming the platform is already dead. It's ironic that the most heated discussions of the platform's weaknesses are playing out on the platform itself. 

For all its faults, and for all they might multiply, Twitter's one advantage is that there's currently no other totally open platform where people can throw their thoughts around in plain, public view. Its greatest threat yet will come not from a new, dodgy feature, but from a new platform – one that can actually compete with it.

Barbara Speed is a technology and digital culture writer at the New Statesman and a staff writer at CityMetric.