Sunday, October 22, 2017

Females Who Mate With Their Brothers and Fathers

Fruit flies... we're talking about fruit flies. Below is the news I found on my own, but first is this take on it by Alex B. Berezow at, provided by a kind friend of FME. Don't be shy about calling my attention to anything relevant to this blog.

The article says "inbreeding" isn't all bad, despite popular notions...
If acted upon by natural selection, bad mutations can be wiped out more easily, thus speeding the rate of evolution. And for some reason, third- and fourth-cousins that marry each other in Iceland have more children.
But what about the fruit flies?
When given a choice between a brother or a non-brother, females preferred mating with their brother. But, males did not prefer their sister. They simply tolerated mating with their sister, picking them roughly half the time. Similarly, females showed no preference when choosing between their father or a non-father, picking their dad about 50% of the time. Males wooed their moms, but no successful mating occurred.
The authors conclude that inbreeding occurs in fruit flies because it may increase their inclusive fitness.
The  article's author makes bigoted comments to make it clear he is disgusted, or at least wants us to think he's disgusted.

Source: Loyau A, Cornuau JH, Clobert J, Danchin É (2012). "Incestuous Sisters: Mate Preference for Brothers over Unrelated Males in Drosophila melanogaster." PLoS ONE 7(12): e51293. doi:10.1371/journal.pone.0051293
I am compelled to point out that consaguinamory and consanguineous sex or marriage do not necessarily mean inbreeding, and most children born to close relatives are healthy. And, as I often mention, what happens with other species, especially ones as different as fruit flies, doesn't necessarily apply to humans. But it is fun to have information like this handy when someone tries to tell you that consanguinamory is unnatural. Funny thing, is, none of these people who say this go a single day of their lives without unnatural things.

Here's the journal piece I had already found on this...
We investigated male and female mate preferences with respect to relatedness in the fruit fly D. melanogaster. Experiments offered the choice between a first order relative (full-sibling or parent) and an unrelated individual with the same age and mating history. We found that females significantly preferred mating with their brothers, thus supporting inbreeding preference. Moreover, females did not avoid mating with their fathers, and males did not avoid mating with their sisters, thus supporting inbreeding tolerance. Our experiments therefore add empirical evidence for inbreeding preference, which strengthens the prediction that inbreeding tolerance and preference can evolve under specific circumstances through the positive effects on inclusive fitness.
The information is extensive, complete with many references. It is good reading for those of you who enjoy scientific journals.
— — —


  1. All I will say is that inbreeding does not automatically lead to children with problems. I have talked with people who were inbred, or who had children with family members, and I have not heard of any who had problems as a result of it. I myself had a daughter with my brother and she has turned out just fine. I am aware that constant inbreeding, generation after generation, can possibly lead to problems, but often times it is not as big a problem as many make it out to be.

    -Liz Smith

    1. When people bring up the mutated baby argument, they forget that most problems arose from several generations of inbreeding. Which coincides with what you said. Most children born from consanguinamory are healthy,

      Those that use cases such as royalty don't realize that that is a case where inbreeding was encouraged if not outright demanded. Most of it was to consolidate power. In the modern day, under non-abuse, most people will not choose to date or have children with a family member, and the frequency is not to be worried about. In other words, I think we would have to require inbreeding for it to become a problem. As it is, tolerance and/or acceptance won't cause it.

      The other part of the coin is that our technology has improved, so we can easily tell if the child will have problems.

      If people want to support eugenics, they need to do so on a consistent level and base it on more practically. They don't really care right now about the child, just filling a moral quota to show off.

    2. Oh my god this comment is perfect! A+! Two thumbs up! You said literally everything I would have said, almost exactly how I would've said it. Weirdly awesome mind-meld moment!

  2. It's also true for human female. If she wasnt taught what she supposed to do. She will choose her brother intuitively instead of any stranger with whom she never dated. Woman seeks mate who are trusted. And family members are the most trusted one.


To prevent spam, comments will have to be approved, so your comment may not appear for several hours. Feedback is welcome, including disagreement. I only delete/reject/mark as spam: spam, vulgar or hateful attacks, repeated spouting of bigotry from the same person that does not add to the discussion, and the like. I will not reject comments based on disagreement, but if you don't think consenting adults should be free to love each other, then I do not consent to have you repeatedly spout hate on my blog without adding anything to the discourse.

If you want to write to me privately, then either contact me on Facebook, email me at fullmarriageequality at protonmail dot com, or tell me in your comment that you do NOT want it published. Otherwise, anything you write here is fair game to be used in a subsequent entry. If you want to be anonymous, that is fine.

IT IS OK TO TALK ABOUT SEX IN YOUR COMMENTS, BUT PLEASE CHOOSE YOUR WORDS CAREFULLY AS I WANT THIS BLOG TO BE AS "SAFE FOR WORK" AS POSSIBLE. If your comment includes graphic descriptions of activity involving minors, it's not going to get published.