KE family
Encyclopedia
The KE family is an extended family, about half of whom exhibit severe forms of specific language impairment
(SLI). The genetic trace across many individuals spanning three generations of the family has been the subject of intense worldwide research since at least 1990, concerning the genetic
origin of language
. In the scientific literature, the family is usually identified as the KE family (sometimes the K family), and as living in London
. Of the 30 members across three generations, about half suffer from severe deficiency, and the other half are normal to various degrees.
The deficiencies reported are that impaired family members "have trouble controlling fine movements in the lower half of their face, and this gives them problems when making the complicated sounds necessary for speech". However, they also have difficulty writing down "as many words as they can think of beginning with a particular letter", which indicates that the pathologies are more profound than that of speech alone.
Clearly the source of this deficit is inherited, which is why the family has been the subject of such interest among geneticists.
In 1998, a short stretch on chromosome
7 of gene FOXP2
, dubbed SPCH1, was identified as being different between the members of the family exhibiting the damage versus those who do not. Subsequently, a particular mutation affecting a specific nucleotide
in the 7q31 region on this gene was found to be broken by a translocation or missense mutation
. Not only did this differ between the speech-impaired and normal members of the KE family, but it was also found to be deficient in one other individual with similar deficiencies.
Research continues on the genetic history of this particular family. In 2002, it was argued that, based on the difference between the human and chimp FOXP2 genes, the language-relevant mutation may have occurred between 10,000 and 100,000 years ago. This may provide a bound on the origins of language – but this link is very tenuous.
Myrna Gopnik
reported on them in 1990. The specific identity of the family does not appear to be publicly known.
Specific language impairment
Specific language impairment is diagnosed when a child's language does not develop normally and the difficulties cannot be accounted for by generally slow development , physical abnormality of the speech apparatus, autistic disorder, acquired brain damage or hearing loss.-Overview:Specific...
(SLI). The genetic trace across many individuals spanning three generations of the family has been the subject of intense worldwide research since at least 1990, concerning the genetic
Genetics
Genetics , a discipline of biology, is the science of genes, heredity, and variation in living organisms....
origin of language
Origin of language
The origin of language is the emergence of language in the human species. This is a highly controversial topic. Empirical evidence is so limited that many regard it as unsuitable for serious scholars. In 1866, the Linguistic Society of Paris went so far as to ban debates on the subject...
. In the scientific literature, the family is usually identified as the KE family (sometimes the K family), and as living in London
London
London is the capital city of :England and the :United Kingdom, the largest metropolitan area in the United Kingdom, and the largest urban zone in the European Union by most measures. Located on the River Thames, London has been a major settlement for two millennia, its history going back to its...
. Of the 30 members across three generations, about half suffer from severe deficiency, and the other half are normal to various degrees.
The deficiencies reported are that impaired family members "have trouble controlling fine movements in the lower half of their face, and this gives them problems when making the complicated sounds necessary for speech". However, they also have difficulty writing down "as many words as they can think of beginning with a particular letter", which indicates that the pathologies are more profound than that of speech alone.
Clearly the source of this deficit is inherited, which is why the family has been the subject of such interest among geneticists.
In 1998, a short stretch on chromosome
Chromosome
A chromosome is an organized structure of DNA and protein found in cells. It is a single piece of coiled DNA containing many genes, regulatory elements and other nucleotide sequences. Chromosomes also contain DNA-bound proteins, which serve to package the DNA and control its functions.Chromosomes...
7 of gene FOXP2
FOXP2
Forkhead box protein P2 also known as FOXP2 is a protein that in humans is encoded by the FOXP2 gene, located on human chromosome 7 . FOXP2 orthologs have also been identified in all mammals for which complete genome data are available...
, dubbed SPCH1, was identified as being different between the members of the family exhibiting the damage versus those who do not. Subsequently, a particular mutation affecting a specific nucleotide
Nucleotide
Nucleotides are molecules that, when joined together, make up the structural units of RNA and DNA. In addition, nucleotides participate in cellular signaling , and are incorporated into important cofactors of enzymatic reactions...
in the 7q31 region on this gene was found to be broken by a translocation or missense mutation
Missense mutation
In genetics, a missense mutation is a point mutation in which a single nucleotide is changed, resulting in a codon that codes for a different amino acid . This can render the resulting protein nonfunctional...
. Not only did this differ between the speech-impaired and normal members of the KE family, but it was also found to be deficient in one other individual with similar deficiencies.
Research continues on the genetic history of this particular family. In 2002, it was argued that, based on the difference between the human and chimp FOXP2 genes, the language-relevant mutation may have occurred between 10,000 and 100,000 years ago. This may provide a bound on the origins of language – but this link is very tenuous.
Myrna Gopnik
Myrna Gopnik
Myrna Gopnik is a Professor Emerita of Linguistics at McGill University. She is known for her discovery of the FOXP2 gene through research on the KE family, an English family with several members affected by specific language impairment...
reported on them in 1990. The specific identity of the family does not appear to be publicly known.