14 research outputs found
Genetic and Environmental Influences on Chinese Language and Reading Abilities
This study investigated the etiology of individual differences in Chinese language and reading skills in 312 typically developing Chinese twin pairs aged from 3 to 11 years (228 pairs of monozygotic twins and 84 pairs of dizygotic twins; 166 male pairs and 146 female pairs). Children were individually given tasks of Chinese word reading, receptive vocabulary, phonological memory, tone awareness, syllable and rhyme awareness, rapid automatized naming, morphological awareness and orthographic skills, and Raven's Coloured Progressive Matrices. All analyses controlled for the effects of age. There were moderate to substantial genetic influences on word reading, tone awareness, phonological memory, morphological awareness and rapid automatized naming (estimates ranged from .42 to .73), while shared environment exerted moderate to strong effects on receptive vocabulary, syllable and rhyme awareness and orthographic skills (estimates ranged from .35 to .63). Results were largely unchanged when scores were adjusted for nonverbal reasoning as well as age. Findings of this study are mostly similar to those found for English, a language with very different characteristics, and suggest the universality of genetic and environmental influences across languages
Large Tandem, Higher Order Repeats and Regularly Dispersed Repeat Units Contribute Substantially to Divergence Between Human and Chimpanzee Y Chromosomes
Comparison of human and chimpanzee genomes has received much attention,
because of paramount role for understanding evolutionary step distinguishing us
from our closest living relative. In order to contribute to insight into Y
chromosome evolutionary history, we study and compare tandems, higher order
repeats (HORs), and regularly dispersed repeats in human and chimpanzee Y
chromosome contigs, using robust Global Repeat Map algorithm. We find a new
type of long-range acceleration, human-accelerated HOR regions. In peripheral
domains of 35mer human alphoid HORs, we find riddled features with ten
additional repeat monomers. In chimpanzee, we identify 30mer alphoid HOR. We
construct alphoid HOR schemes showing significant human-chimpanzee difference,
revealing rapid evolution after human-chimpanzee separation. We identify and
analyze over 20 large repeat units, most of them reported here for the first
time as: chimpanzee and human ~1.6 kb 3mer secondary repeat unit (SRU) and
~23.5 kb tertiary repeat unit (~0.55 kb primary repeat unit, PRU); human 10848,
15775, 20309, 60910, and 72140 bp PRUs; human 3mer SRU (~2.4 kb PRU); 715mer
and 1123mer SRUs (5mer PRU); chimpanzee 5096, 10762, 10853, 60523 bp PRUs; and
chimpanzee 64624 bp SRU (10853 bp PRU). We show that substantial
human-chimpanzee differences are concentrated in large repeat structures, at
the level of as much as ~70% divergence, sizably exceeding previous numerical
estimates for some selected noncoding sequences. Smeared over the whole
sequenced assembly (25 Mb) this gives ~14% human--chimpanzee divergence. This
is significantly higher estimate of divergence between human and chimpanzee
than previous estimates.Comment: 22 pages, 7 figures, 12 tables. Published in Journal of Molecular
Evolutio