{"id":7722,"date":"2013-02-25T17:43:29","date_gmt":"2013-02-25T22:43:29","guid":{"rendered":"http:\/\/www.starshipnivan.com\/blog\/?p=7722"},"modified":"2013-02-26T14:41:07","modified_gmt":"2013-02-26T19:41:07","slug":"the-language-gene-and-womens-wagging-tongues","status":"publish","type":"post","link":"https:\/\/starshipnivan.com\/blog\/?p=7722","title":{"rendered":"The “Language” Gene and Women’s Wagging Tongues"},"content":{"rendered":"

\u00a0Aka, How to Twist Science to Reinforce Gender Stereotypes<\/strong><\/p>\n

Note:<\/strong> this article first appeared as a guest blog post<\/a> in Scientific American. Not surprisingly, some were dissatisfied: primarily, those who still like to think that genes determine higher-order behavior and that “gender” differences are hardwired and extensive. Excerpt of an interminable pseudo-learned comment at the SciAm blog: “In fact, it can be argued that the differences between genders is far more distinct and pervasive than the differences between species.”\u00a0 Satoshi Kanazawa, is that you?<\/p>\n

\"FOXP2<\/a><\/p>\n

Stylized rendering of FOXP2 attached to DNA (Wikipedia, CCL)<\/p>\n

Genes are subject to multiple layers of regulation.\u00a0 An early regulatory point is transcription.\u00a0 During this process, regulatory proteins bind to DNA regions (promoters and enhancers) that direct gene expression.\u00a0 These DNA\/protein complexes attract the transcription apparatus, which docks next to the complex and proceeds linearly downstream, producing the heteronuclear (hn) RNA that is encoded by the gene linked to the promoter.\u00a0 The hnRNA is then spliced and either becomes structural\/regulatory RNA or is translated into protein.<\/p>\n

Transcription factors are members of large clans that arose from ancestral genes that went through successive duplications and then diverged to fit specific niches.\u00a0 One such family of about fifty members is called FOX. \u00a0Their DNA binding portion is shaped like a butterfly, which has given this particular motif the monikers of forkhead box or winged helix.\u00a0 The activities of the FOX proteins extend widely in time and region.\u00a0 One of the FOX family members is FOXP2, as notorious as Fox News \u2013 except for different reasons: FOXP2 has become entrenched in popular consciousness as \u201cthe language gene\u201d.\u00a0 As is the case with all such folklore, there is some truth in this; but as is the case with everything in biology, reality is far more complex.<\/p>\n

FOXP2, the first gene found to \u201caffect language\u201d (more on this anon), was discovered in 2001 by several converging observations and techniques.\u00a0 The clincher was a large family (code name KE), some of whose members had severe articulation and grammatical deficits with no accompanying sensory or cognitive impairment.\u00a0 The inheritance is autosomal dominant: one copy of the mutated gene is sufficient to confer the trait. \u00a0When the researchers definitively identified the FOXP2 gene, they found that the version of FOXP2 carried by the KE affected members has a single point mutation that alters an invariant residue in its forkhead domain, thereby influencing the protein\u2019s binding to its DNA targets.<\/p>\n

Like all transcription factors, FOXP2 regulates many promoters. \u00a0The primary domains of FOXP2 influence are brain and lung development.\u00a0 Some of its downstream targets are themselves regulators of brain function (most prominently neurexin CNTNAP2).\u00a0 Not surprisingly, deleting or mutating both FOXP2 copies in mice results in early death, whereas doing so to one copy leads to decreased vocalization and slightly impaired motor learning. \u00a0FOXP2 is broadly conserved across vertebrates, but its critical functional regions have tiny but telling differences even between humans and their closest ape relatives.\u00a0 Like other genes that influence human-specific attributes, human FOXP2 seems to have undergone positive selection during the broad intervals of crucial speciation events.\u00a0 Along related lines, Neanderthals and Denisovans apparently had the same FOXP2 allele as contemporary humans, and by this criterion were fully capable of the articulation that makes language possible.<\/p>\n

Which brings us to the nub of the issue.\u00a0 What does FOXP2 do in brain?\u00a0 Genes don\u2019t encode higher-order functions, let alone behavior.\u00a0 Also recall that the KE family members have a very circumscribed defect, despite its dramatic manifestation.\u00a0 Finally, keep firmly in mind that language in humans includes a complex genetic component that involves many loci and just as many environmental interactions.\u00a0 FOXP2 does not encode inherent language ability.\u00a0 Instead, the time and place of its expression as well as studies in cell systems and other organisms (zebra finches, rodents) indicate that FOXP2 may be involved in neuronal plasticity, which in turn modulates capacity for learning by forming new synaptic connections.\u00a0 FOXP2 may also be involved in regulation of motor neuron control in certain brain regions (cortical motor areas, cerebellum, striatum) that affect the ability to vocalize, sing and, in humans, form the complex sounds of language.<\/p>\n

Given its connection, however over-interpreted, to \u201cwhat makes a human\u201d as well as its chromosomal location (in 7q31, which also harbors candidates for autism and dementia), it\u2019s not surprising that FOXP2 has acquired quasi-mythic dimensions in the lay imagination.\u00a0 However, careful studies have shown that the genes on 7q31 responsible for autism and dementia are distinct from FOXP2.\u00a0 Also, as I said earlier, FOXP2 does not code for language ability \u2013 and even less for its culturally determined manifestations (many of which are a minefield of confirmation biases, unquestioned assumptions and simply sloppy work).<\/p>\n

\"Gender<\/a>The latest round in the misrepresentation of FOXP2 is the gone-viral variation of \u201cthere\u2019s more of this \u2018language protein\u2019 in the left hemisphere of 4-year girls and that\u2019s why women are three times as talkative as men\u201d.\u00a0 This came from the PR pitch of a research team who did a study primarily on rats (which confirmed the link between FOXP2 levels and vocalization) and then, perhaps attempting to latch onto a catchy soundbite, extended the gender link to humans based on\u2026 a single PCR amplification of ten Broca\u2019s area cortices (from postmortem brains of 4-year olds, five from each sex; Broca\u2019s area is involved in language processing).<\/p>\n

To begin with, all studies conducted so far definitively show that women and men utter the same number of words by any metric chosen \u2013 and that in fact men talk more than women in mixed-gender conversations (to say nothing of the gender-linked ratio of interruptions).\u00a0 And whereas it\u2019s true that girls develop vocal competence slightly earlier than boys and show higher linguistic skills during the early acquisition window, this difference is transient.\u00a0 Furthermore, the FOXP1 control that the authors of the study argue does not show a gender-correlated change (unlike FOXP2) in fact is on the verge of doing so, and the relative statistical significances might well change if a larger number of samples were tested.\u00a0 Finally, whereas decrease of FOXP2 reduces vocalization and increases pitch in male rat pups, it has the opposite effect in female rat pups.\u00a0 In other words, the correlation between FOXP2 levels and vocalization\/pitch is not straightforward even in rats.<\/p>\n

In the larger context of expression and reception of vocalizations, the difference is not how much women talk, but how welcome and\/or valued their input is.\u00a0 Even trivial zomboid blathering is given higher value if it\u2019s culturally coded as masculine (examples: sport newscasters; most congressmen).\u00a0 In fairness to the researchers of the study that caused all this rehashing of kneejerk stereotypes and evopsycho Tarzanism, here is the concluding paragraph of their paper.\u00a0 It states something both measured and, frankly, obvious:<\/p>\n

\u201cGender is a purely human construct consisting of both self and others\u2019 perception of one\u2019s sex and is arguably the first and most salient of all phenotypic variables. Sex differences in how language is received and processed and how speech is produced has the potential to influence gender both within and external to an individual. Whether human sex differences in FOXP2, and possibly FOXP1 as well, contribute to gender variation in language is a question for future research.\u201d<\/p><\/blockquote>\n

Relevant publications and links:<\/b><\/p>\n

Lai CS, Fisher SE, Hurst JA, Vargha-Khadem F, Monaco AP (2001).\u00a0 A forkhead-domain gene is mutated in a severe speech and language disorder.<\/a> \u00a0Nature 413(6855):519-23.<\/p>\n

White SA, Fisher SE, Geschwind DH, Scharff C, Holy TE (2006).\u00a0 Singing mice, songbirds, and more: models for FOXP2 function and dysfunction in human speech and language.<\/a> \u00a0J. Neurosci. 26(41):10376-9.<\/p>\n

Bowers JM, Perez-Pouchoulen M, Edwards NS, McCarthy MM (2013).\u00a0 FOXP2 mediates sex differences in ultrasonic vocalization by rat pups and directs order of maternal retrieval.<\/a>\u00a0 J. Neurosci. 33(8):3276-83.<\/p>\n

Mark Liberman.\u00a0 Gabby Guys: The Effect size<\/a> (Language Log, Sept. 23, 2006)<\/p>\n

Mark Liberman.\u00a0 An Invented Statistic Returns<\/a> (Language Log, Feb. 22, 2013)<\/p>\n

Athena Andreadis.\u00a0 Eldorado Desperadoes: Of Mice and Men<\/a> (Starship Reckless, July 18, 2009)<\/p>\n

Athena Andreadis.\u00a0 Miranda Wrongs: Reading Too Much into the Genome<\/a> (Starship Reckless, June 10, 2011)<\/p>\n","protected":false},"excerpt":{"rendered":"

\u00a0Aka, How to Twist Science to Reinforce Gender Stereotypes Note: this article first appeared as a guest blog post in Scientific American. Not surprisingly, some were dissatisfied: primarily, those who still like to think that genes determine higher-order behavior and that “gender” differences are hardwired and extensive. Excerpt of an interminable pseudo-learned comment at the […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[6,10],"tags":[],"class_list":["post-7722","post","type-post","status-publish","format-standard","hentry","category-biology-and-culture","category-science"],"_links":{"self":[{"href":"https:\/\/starshipnivan.com\/blog\/index.php?rest_route=\/wp\/v2\/posts\/7722","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/starshipnivan.com\/blog\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/starshipnivan.com\/blog\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/starshipnivan.com\/blog\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/starshipnivan.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=7722"}],"version-history":[{"count":0,"href":"https:\/\/starshipnivan.com\/blog\/index.php?rest_route=\/wp\/v2\/posts\/7722\/revisions"}],"wp:attachment":[{"href":"https:\/\/starshipnivan.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=7722"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/starshipnivan.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=7722"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/starshipnivan.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=7722"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}