What Makes Someone Monogamous?

Wedding rings (BBC)

Wedding rings (BBC)

We can’t distill monogamy into a single magic formula. But some scientists have recently made strides in determining what factors might make a person monogamous.

One possible factor: genetics.

Researchers at Harvard University recently published a study examining the mating habits of deer mice and oldfield mice. In the wild, deer mice are promiscuous and oldfield mice are monogamous. Scientists first undertook an experiment to see how the two types of mice compare in parenting their young. Different parenting metrics were observed, such as building nests for the offspring.

After noting that the deer mice put in less parental efforts, the researchers wanted to see if the differences were down to genetics (ah, the old nature vs. nurture debate!). Five pairs of deer mice and oldfield mice were interbred, which produced 30 hybrid mice and later 769 (!) third-generation mice.

The parenting behaviors of these second- and third-generation hybrid mice ran the gamut from hardly involved to heavily-involved in their offsprings’ lives. In observing this, scientists were able to identify parts of DNA (termed loci) that determined parenting behaviors. The experiment’s abstract in scientific journal Nature explained the findings:

Using quantitative genetics, we identify 12 genomic regions that affect parental care, 8 of which have sex-specific effects, suggesting that parental care can evolve independently in males and females. Furthermore, some regions affect parental care broadly, whereas others affect specific behaviours, such as nest building.

The abstract also notes that a certain gene expression is primarily responsible for the level of nest-building. No word on how that would translate to humans (the gene for interior decorating?), but it’s exciting to see some strides made in genetic research.

Lucy and Maria Aylmer: How Many Twins Look Racially Different?

Twin sisters Lucy and Maria Aylmer (BoredPanda)

Twin sisters Lucy and Maria Aylmer (BoredPanda)

This week, the Internet has been fascinated by a set of English fraternal twins Lucy and Maria Aylmer. But there’s something special about them: Lucy has pale skin and red hair, while Maria has brown skin and brown curly hair.

In other words, one twin looks white, and the other twin looks black.

Their parents have a mixed racial background: their mother is half Jamaican, and their father is white.

Occasionally, stories like theirs pop up every now and again. In 2009, another British mixed-race couple produced not one, but two, sets of identical twins who each looked very racially different from their sibling.

But how common is this?

Unfortunately, there are no statistics that track this. From “The Associated Press:”

The phenomenon is so uncommon that there are no statistics to illustrate its probability, although it is thought likely to become more common because of the growing number of mixed-race couples.

To give you an idea on exactly how uncommon this is (using numbers!), Dr. Sarah Jarvis of Britain’s Royal College of General Pracitioners, said in 2009 (though it still applies today):

“Even non-identical twins aren’t that common. Non-identical twins from mixed parents, of different races, less common still. To have two eggs fertilized and come out different colors, less common still. So, to have it happen twice must be one in millions.”

But that’s just a guess, though the BBC reported chances closer to 1 in 500 in 2011. We won’t know until we actually start tracking the numbers.

The UK Introduces “3-Parent Baby” Bill

Human embryos (Bloomberg)

Human embryos (Bloomberg)

Britain made history this week by becoming the first country to introduce a “3-parent baby” bill.

Approved by the House of Commons, the Human Fertilization and Embryology (Mitochondrial Donation) Regulations 2015 seeks to eradicate genetic diseases that are passed from mother to child via defective mitochondria. (Defective mitochondria causes diseases such as brain damage, heart failure and blindness.) The genetic diseases would then cease to be passed to future generations.

For those who aren’t up on their fifth-grade science, here’s how it works: There are two healthy parents, save for the defective mitochondria (the cells that convert food into energy). A third woman would donate her healthy mitochondria via a modified in-vitro fertilization (IVF) technique. From then on, the mitochondria are permanently altered for the better.

There are two ways the procedure can be executed. For visual learners, diagrams are below:

Method 1 - Embryo Repair (BBC)

Method 1 – Embryo Repair (BBC)

In the first method, the nuclei from the parents’ fertilized embryo is added to the donor’s fertilized embryo. The modified embryo is then placed into the womb.

Method 2 - Egg Repair (BBC)

Method 2 – Egg Repair (BBC)

In the second method, the nucleus from the mother’s egg is placed into the donor egg, with the healthy mitochondria.

In fact, calling a resulting baby from the procedure a “3-parent baby” is a misnomer: The donor would only give about .1% of her DNA. It would only change the portion that houses the genetic disease. Per the BBC, reproductive ethicist Dr. Gillian Lockwood notes:

Less than a tenth of one per cent of the genome is actually going to be affected. It is not part of what makes us genetically who we are. It doesn’t affect height, eye colour, intelligence, musicality.

If the measure passes through the House of Lords, the first baby to benefit from this procedure could be born next year.

NPR notes that U.S. agencies, such as the Food and Drug Administration (FDA) have also been looking into the process, since 1-4K American children are born with a mitochondrial disease (numbers per the United Mitochondrial Disease Foundation).

It’s safe to say that Britain will pave the way with how they handle this measure, and the world will be watching (and learning).