Culture May Be Encoded in DNA

Knowledge is passed down directly from generation to generation in the animal kingdom as parents teach their children the things they will need to survive. But a new study has found that, even when the chain is broken, nature sometimes finds a way.

Zebra finches, which normally learn their complex courtship songs from their fathers, spontaneously developed the same songs all on their own after only a few generations.

“We found that in this case, the culture was pretty much encoded in the genome,” said Partha Mitra of Cold Spring Harbor Laboratory in New York, co-author of a study in Nature on Sunday.

Birds transmit their songs through social interactions, as humans do for languages, dances, cuisine and other cultural elements. Though birds and humans have clearly followed different evolutionary paths, birdsong culture can still inform theories of human culture.

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Blip wrote:I was struck by this extract:

Zebra finches, which normally learn their complex courtship songs from their fathers, spontaneously developed the same songs all on their own after only a few generations.

This doesn't demonstrate that the songs are encoded in their DNA, though: rather it demonstrates similar behaviour arising in response to similar environmental pressures, does it not?

katja z wrote:

Blip wrote:I was struck by this extract:

Zebra finches, which normally learn their complex courtship songs from their fathers, spontaneously developed the same songs all on their own after only a few generations.

This doesn't demonstrate that the songs are encoded in their DNA, though: rather it demonstrates similar behaviour arising in response to similar environmental pressures, does it not?

I've been wondering about this too, the pressure in this case would be provided by female finches and it isn't clear to me from the text whether the males in the experiment had any interaction with those. Feedback from their target audience would explain this nicely.

Blip wrote:I was struck by this extract:

Zebra finches, which normally learn their complex courtship songs from their fathers, spontaneously developed the same songs all on their own after only a few generations.

This doesn't demonstrate that the songs are encoded in their DNA, though: rather it demonstrates similar behaviour arising in response to similar environmental pressures, does it not?

katja z wrote:

Blip wrote:I was struck by this extract:

Zebra finches, which normally learn their complex courtship songs from their fathers, spontaneously developed the same songs all on their own after only a few generations.

This doesn't demonstrate that the songs are encoded in their DNA, though: rather it demonstrates similar behaviour arising in response to similar environmental pressures, does it not?

I've been wondering about this too, the pressure in this case would be provided by female finches and it isn't clear to me from the text whether the males in the experiment had any interaction with those. Feedback from their target audience would explain this nicely.

Jie wrote:

katja z wrote:

Blip wrote:I was struck by this extract:

Zebra finches, which normally learn their complex courtship songs from their fathers, spontaneously developed the same songs all on their own after only a few generations.

This doesn't demonstrate that the songs are encoded in their DNA, though: rather it demonstrates similar behaviour arising in response to similar environmental pressures, does it not?

I've been wondering about this too, the pressure in this case would be provided by female finches and it isn't clear to me from the text whether the males in the experiment had any interaction with those. Feedback from their target audience would explain this nicely.

I'm no expert, but wouldn't the fact that it took a few generations for the songs to manifest sort of imply the presence of females? Kind of hard to extract sperm from a male bird, I would think...

katja z wrote::tehe: They could do as with the first generation, remove the eggs from the nests before hatching. I took "generation" to refer to the roles of "teachers" and "students", not to descent.

Mitra’s team wanted to find out what would happen if an isolated bird raised his own colony. As expected, birds raised in soundproof boxes grew up to sing cacophonous songs.

But then scientists let the isolated birds give voice lessons to a new round of hatchlings. They found that the young males imitated the songs — but they tweaked them slightly, bringing the structure closer to that of songs sung in the wild. When these birds grew up and became tutors, their pupils’ song continue to conform, with tweaks.

After three to four generations, the teachers were producing strapping young finches that belted out normal-sounding songs.

Experimental design

We used zebra finches (Taeniopygia guttata) from the City College breeding colony. Colony management and isolation procedures have been described previously29. Except for the colony experiment, all birds were kept either singly (isolates) or in pairs (one-to-one tutored) in sound attenuation chambers (Supplementary Information, section 3e) betweens days 30 and 120 post hatch. WT songs (n = 52) were obtained from birds raised in two well-established colonies. Isolates (n = 17) were raised by their mothers from day 7 to day 29 post hatch and were kept in complete isolation from day 30 until day 120 or later. One-to-one-tutored birds (n = 13 and 8 for first and later generations, respectively) were randomly selected from 40 breeding pairs and paired with one of six isolate tutors on day 30. For the colony setting, we made a sound isolation chamber from an inoperational 20-ft3 refrigerator (Supplementary Fig. 1). All birds in the colony (except for the three female founders) were the descendants of the founder male.

It is also interesting to note that during the first
days after hatching the parents tend to be very quite (sic), and if the males sing at all, they tend
to sing away from the nest, facing the other way (Tchernichovski et al, Animal Behav.
1998).

Mr.Samsa wrote:
That's not the best part though, this is:

It is also interesting to note that during the first
days after hatching the parents tend to be very quite (sic), and if the males sing at all, they tend
to sing away from the nest, facing the other way (Tchernichovski et al, Animal Behav.
1998).

So it's okay, because they're usually rather quiet when they sing around the offspring (I guess so they don't wake them, everyone hates a crying baby), and usually they'll face the other way when they do sing (presumably to prevent the offspring from lip reading?).

Even if we assume that the methodology was sound, the strongest conclusion we can reach from this is that their bird song is constrained by biology in some way (i.e. some sounds are easier to form that others which dictates the basic shape of the song), and over time the birds are able to figure out the best way to put these sounds together.

katja z wrote:


The lipreading finches totally made my day! Thanks for ferreting out the original paper.

Culture is typically viewed as consisting of traits inherited epigenetically, through social learning. However, cultural diversity has species-typical constraints1, presumably of genetic origin. A celebrated, if contentious, example is whether a universal grammar constrains syntactic diversity in human languages2. Oscine songbirds exhibit song learning and provide biologically tractable models of culture: members of a species show individual variation in song3 and geographically separated groups have local song dialects4, 5. Different species exhibit distinct song cultures6, 7, suggestive of genetic constraints8, 9. Without such constraints, innovations and copying errors should cause unbounded variation over multiple generations or geographical distance, contrary to observations9. Here we report an experiment designed to determine whether wild-type song culture might emerge over multiple generations in an isolated colony founded by isolates, and, if so, how this might happen and what type of social environment is required10. Zebra finch isolates, unexposed to singing males during development, produce song with characteristics that differ from the wild-type song found in laboratory11 or natural colonies. In tutoring lineages starting from isolate founders, we quantified alterations in song across tutoring generations in two social environments: tutor–pupil pairs in sound-isolated chambers and an isolated semi-natural colony. In both settings, juveniles imitated the isolate tutors but changed certain characteristics of the songs. These alterations accumulated over learning generations. Consequently, songs evolved towards the wild-type in three to four generations. Thus, species-typical song culture can appear de novo. Our study has parallels with language change and evolution12, 13, 14. In analogy to models in quantitative genetics15, 16, we model song culture as a multigenerational phenotype partly encoded genetically in an isolate founding population, influenced by environmental variables and taking multiple generations to emerge.

katja z wrote:

Even if we assume that the methodology was sound, the strongest conclusion we can reach from this is that their bird song is constrained by biology in some way (i.e. some sounds are easier to form that others which dictates the basic shape of the song), and over time the birds are able to figure out the best way to put these sounds together.

I think it would also be reasonable to suppose that the song preferred by females would at least sound nice to the males as well, so they could use their own preferences as a guideline?

ZedTheLiberator wrote:The second problem I have with this is larger, namely that there is no real mechanism that I know of for somehow transmitting learned information to the genome.

DanDare wrote: Isolate some kids and have them somehow grow up together without direct adult contact and they will build a vocabulary and grammar of some sort. That is "encoded" in their DNA.

katja z wrote:

DanDare wrote: Isolate some kids and have them somehow grow up together without direct adult contact and they will build a vocabulary and grammar of some sort. That is "encoded" in their DNA.

No they won't and no it isn't. Check the thread on the "language instinct" and particularly my latest post on the creole argument (which is what you are probably referring to, even though in a simplified form - even Bickerton required kids to have their parents' pidgin to work on).