The Sequence Organization of Yp/Proximal Xq Homologous Regions of the Human Sex Chromosomes Is Highly Conserved

Sargent, Carole A.; Briggs, Hayley; Chalmers, I.Jennifer; Lambson, Bronwen E.; Walker, Elizabeth; Affara, Nabeel A.

doi:10.1006/geno.1996.0106

Cited by 64 publications

(42 citation statements)

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“…Instead, this zone is distinctly more distal, roughly at the center of mass of the chromosome. It begins at or very near the X-inactivation center of the chromosome, the XIST locus (Lyon 1992) and extends distally to another distinctive region that has been delineated by the map, -4 Mb of DNA homologous on the X and Y chromosomes (Sargent et al 1996). The conjunction of the XIST locus, with one edge of an extensive region of low recombination, is suggestive.…”

Section: Recombination Indices Compared To Locationmentioning

confidence: 99%

X chromosome map at 75-kb STS resolution, revealing extremes of recombination and GC content.

Nagaraja

MacMillan²,

Kere³

et al. 1997

Genome Res.

111

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In addition to sustaining an exponentially increasing rate of gene finding (Collins 1995), yeast artificial chromosome/sequence-tagged site (STS/YAC)-based maps (Burke et al. 1987;Olson et al. 1989) have begun to reveal additional features of chromosome structure and dynamics. For example, during the development of maps for subportions of the X chromosome, the existence of a second "pseudoautosomal" region at the Xq terminus of the chromosome was demonstrated (Freije and Schlessinger 1992;Li and Hamer 1995), followed by the discovery that the region shows a unique phenomenon of gene inactivation on both the X and Y homologs (D'Esposito et al. 1996). In another instance, it was shown that a cluster of genes in a delimited segment of XpI 1 escape X inactivation (Miller et al. 1995). As the density of markers across the chromosome has increased beyond the 100-kb resolution goal suggested for the 1Corresponding author. E-MAIL davids@sequencer.wustl.edu; FAX (314) 362-3203."genome initiative," additional features are revealed, as described here.The average inter-STS distance of-75 kb has been achieved by the placement of 2091 STSs on cognate YACs across the 160 Mb of the chromosome. Collectively, the STSs sample -1% of Xspecific sequences. About half of the STSs (962) are made from YAC insert ends (Kere et al. 1992), and another 592 are from randomly derived unique Xchromosomal sequences. However, the STSs also include 97 expressed sequence tags (ESTs) and 190 gene-specific STSs from known genes, as well as 192 dinucleotide and 38 tri-and tetranucleotide repeat markers that detect polymorphism. As a result, the YAC/STS map can be integrated with transcriptional and genetic maps. RESULTS Mapping Strategy and PerformanceWe used a modified "all-walking" form of STS content mapping (Kere et al. 1992) in which STSs were

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Section: Recombination Indices Compared To Locationmentioning

confidence: 99%

X chromosome map at 75-kb STS resolution, revealing extremes of recombination and GC content.

Nagaraja

MacMillan²,

Kere³

et al. 1997

Genome Res.

111

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show abstract

“…These sequences are compared to the element (SINE-R.C2) originally identified in the C2 complement gene that is human specific (Zhu et al, 1994), to those elements (SINE-R11, R14, and R19) earlier reported in the human genome (Ono et al, 1987) and present also in hominoid primates (Kim et al, 1999a,b,c), to an element identified in the fragile X mental retardation gene (FMR-1), and to the elements we have identified on the 7, 17, and Y chromosomes Crow, 1999, 2000) and in cDNA (SCHIZO) from postmortem brain. Also included are two elements (HS307 and 408) already located (Kim et al, 1999b) in the Xq21.3 region of homology to Yp (Sargent et al, 1996) that was generated after the separation of the chimpanzee and human lineages by a retroposition from the X to the Y chromosomes.…”

Section: Resultsmentioning

confidence: 99%

“…Besides the pseudoautosomal regions, within which there is recombination in male meiosis, and therefore strict homology of sequences on the X with those on the Y, a number of blocks of X-Y homology have been identified Lambson et al, 1992) and their origins in primate evolution, often by translocation from the X to the Y chromosome, determined. It will be interesting to examine whether the HS307 and HS408 sequences that we have identified within the Xq21.3 region (Kim et al, 1999b) are present within the block of homology in Yp that was generated after the separation of the chimpanzee and human lineages (Sargent et al, 1996).…”

Section: Resultsmentioning

confidence: 99%

Phylogenetic analysis of a retroposon family as represented on the human X chromosome.

et al. 2000

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SINE-R elements constitute a class of retroposons derived from the long terminal repeat (LTR) of the human endogenous retrovirus HERV-K family that are present in hominoid primates and active in the human genome. In an investigation of the X chromosome, we identified twenty-five SINE-R elements with between 89.6 and 97.7% homology with the SINE-R.C2 element that is human specific, originally identified in the gene for the C2 component of complement. SINE-R.C2 and a sequence HS307 that we previously identified in a region of Xq21.3 that has a recently created homology with a 4 Mb block in Yp11.2 are amongst the group of elements that have diverged furthest from the parent HERV-K10 sequence. The sequences on the X chromosome resemble those that we previously described on chromosomes 7 and 17 and the Y chromosome, with a similar range of variation. Phylogenetic analysis from the retroposon family including those of African great apes using the neighbor-joining method suggests that the SINE-R retroposon family have evolved independently during primate evolution. Further investigation of SINE-R elements on the sex chromosomes, particularly in recently created regions of X-Y homology, may cast light on the timing of the retroposition process and its possible relevance to recent evolutionary change.

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“…La expresión de ambos genes sería diferente en los dos sexos, puesto que el gen PCDHX [PCDH11X] escapa, en particular, al proceso general de inactivación que afecta característicamente a los genes contenidos en el cromosoma X, de ahí que sus niveles de expresión en los individuos de sexo femenino dupliquen los observados en los de sexo masculino (Lopes et al, 2006). El gen PCDHY [PCDH11Y] es el resultado de un proceso de transposición al cromosoma Y de una copia del gen PCDHX [PCDH11X], el cual tuvo lugar hace entre tres y cuatro millones de años, tras la separación de la línea evolutiva que condujo a la aparición de la especie humana de la que dio lugar a las restantes especies actuales de primates (Sargent et al, 1996), de ahí que esté ausente en dichas especies (Wilson et al, 2006) y que no se observe en ellas la disparidad sexual en el grado de lateralización, ni consecuentemente de habilidad manual, que aparece característicamente en nuestra especie. En todo caso, lo relevante en el contexto de este artículo es el hecho de que la datación del evento de reorganización cromosómica se aproxima en buena medida a la datación sugerida por las evidencias fósiles de la lateralización funcional a las que se hizo referencia anteriormente (los primeros restos del Homo ergaster tienen una antigüedad de alrededor de dos millones de años [Arsuaga et al, 2000]).…”

Section: ¿Existen Otras Evidencias Al Margen De Las De Tipo Fósil Capunclassified

La lateralización cerebral y el origen del lenguaje

Benítez‐Burraco¹

2007

ELUA

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ResumenEl "órgano del lenguaje" se encuentra lateralizado en términos estructurales y funcionales. Se ha prestado una especial atención a aquellas evidencias fósiles que parecen sugerir la existencia en especies de homínidos extintas de una lateralización cerebral de carácter estructural y funcional semejante a la que se advierte en los humanos, que podrían ser un indicio de la disponibilidad de una (cierta) capacidad de procesamiento lingüístico. Evidencias adicionales han aportado nuevos datos sobre los principales hitos que habrían jalonado dicho itinerario evolutivo, en particular, en lo que concierne a la cuestión de la lateralización y su relación con el lenguaje. El objetivo de este trabajo es tratar de valorar críticamente todas estas evidencias, así como las inferencias realizadas a partir de ellas sobre las capacidades lingüísticas de otras especies de homínidos. La conclusión fundamental será que, mientras que las evidencias fósiles parecen enfrentarse a dificultades inherentes a la asunción de una homología funcional, allí donde parece existir (sólo) una homología estructural, las evidencias de naturaleza molecular parecen asumir una concepción demasiado simplista de las relaciones que se establecen entre los genes y la cognición. El artículo concluirá bosquejando un modelo evolutivo general del "órgano del lenguaje" más ajustado al creciente corpus de datos genéticos y moleculares. PALABRAS CLAVE: lateralización cerebral, evidencias fósiles, biología molecular, evolución del lenguaje AbstractThe "language organ" seems to be lateralised both structurally and functionally. When trying to discern how language evolved, fossil evidences concerning structural and functional brain lateralization have been regularly considered, and a (rudimentary) language faculty have tentatively been inferred for some extinct hominid species. Further evidences, mainly concerning brain gene evolution, have also been recently taken into account when trying to determine phylogenetic relationships between brain lateralization and language. This growing body of evidences are critically examined in this paper. A main conclusion will be that fossil evidences often lead to wrongly infer functional homology from structural homology, whereas molecular data are frequently linked to simplistic conceptions of the genuine connection between genes and cognition. Consequently, a tentative model for accounting the evolution of the language organ will be outlined, mainly based on genetic and molecular data.

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The Sequence Organization of Yp/Proximal Xq Homologous Regions of the Human Sex Chromosomes Is Highly Conserved

Cited by 64 publications

References 0 publications

X chromosome map at 75-kb STS resolution, revealing extremes of recombination and GC content.

X chromosome map at 75-kb STS resolution, revealing extremes of recombination and GC content.

Phylogenetic analysis of a retroposon family as represented on the human X chromosome.

La lateralización cerebral y el origen del lenguaje

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