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MCPH1
Microcephalin (MCPH1) is a gene that is expressed during fetal brain development. Certain mutations in ''MCPH1'', when homozygous, cause primary microcephaly—a severely diminished brain. Hence, it has been assumed that variants have a role in brain development. However, in normal individuals no effect on mental ability or behavior has yet been demonstrated in either this or another similarly studied microcephaly gene, '' ASPM''. However, an association has been established between normal variation in brain structure, as measured with MRI (i.e., primarily '' cortical surface area'' and total brain volume) but only in females, and common genetic variants within both the MCPH1 gene and another similarly studied microcephaly gene, '' CDK5RAP2''. Structure Microcephalin proteins contain the following three domains: * N-terminal BRCT domain * Central microcephalin protein domain () * C-terminal BRCT domain Expression in the brain MCPH1 is expressed in the fetal brain, in the deve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microcephaly
Microcephaly (from New Latin ''microcephalia'', from Ancient Greek μικρός ''mikrós'' "small" and κεφαλή ''kephalé'' "head") is a medical condition involving a smaller-than-normal head. Microcephaly may be present at birth or it may develop in the first few years of life. Since brain growth is correlated with head growth, people with this disorder often have an intellectual disability, poor motor function, poor speech, abnormal facial features, seizures and dwarfism. The disorder is caused by a disruption to the genetic processes that form the brain early in pregnancy, though the cause is not identified in most cases. Many genetic syndromes can result in microcephaly, including chromosomal and single-gene conditions, though almost always in combination with other symptoms. Mutations that result solely in microcephaly (primary microcephaly) exist but are less common. External toxins to the embryo, such as alcohol during pregnancy or vertically transmitted infec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bruce Lahn
Bruce Lahn is a Chinese-born American geneticist. Lahn came to the U.S. from China to continue his education in the late 1980s. He is the William B. Graham professor of Human Genetics at the University of Chicago. He is also the founder of the Center for Stem Cell Biology and Tissue Engineering at Sun Yat-sen University in Guangzhou, China. Lahn currently serves as the chief scientist of VectorBuilder, Inc. Lahn's honors include the Merrill Lynch Forum Global Innovation Award, the TR100 Award from ''Technology Review'', the Burroughs Wellcome Career Award, and a Searle Scholarship. He was also named to the 40-Under-40 list by Crains Chicago Business. Lahn received his B.A. in General Biology from Harvard University and his Ph.D. from the Massachusetts Institute of Technology in the lab of David C. Page. From 2000 to 2012, Lahn was a Howard Hughes Medical Institute sponsored Investigator. His previous research specialized in human genetics and evolutionary genetics, especially hu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
BRCT Domain
BRCA1 C Terminus (BRCT) domain is a family of evolutionarily related proteins. It is named after the C-terminal domain of BRCA1, a DNA-repair protein that serves as a marker of breast cancer susceptibility. The BRCT domain is found predominantly in proteins involved in cell cycle checkpoint functions responsive to DNA damage, for example as found in the breast cancer DNA-repair protein BRCA1. The domain is an approximately 100 amino acid tandem repeat, which appears to act as a phospho-protein binding domain. Examples Human proteins containing this domain include: * BARD1; BRCA1 * CTDP1; TDT or DNTT * ECT2 * LIG4 * MCPH1; MDC1 * NBN * PARP1; PARP4; PAXIP1; PES1 * REV1; RFC1; TOPBP1; TP53BP1; XRCC1 DNA repair protein XRCC1, also known as X-ray repair cross-complementing protein 1, is a protein that in humans is encoded by the ''XRCC1'' gene. XRCC1 is involved in DNA repair, where it complexes with DNA ligase III. Function XRCC1 is invol ... References External l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ASPM (gene)
Abnormal spindle-like microcephaly-associated protein, also known as abnormal spindle protein homolog or Asp homolog, is a protein that in humans is encoded by the ''ASPM'' gene. ASPM is located on chromosome 1, band q31 (1q31). The ''ASPM'' gene contains 28 exons and codes for a 3477 amino‐acid‐long protein. The ASPM protein is conserved across species including human, mouse, ''Drosophila'', and ''C. elegans''. Defective forms of the ASPM gene are associated with autosomal recessive primary microcephaly. "ASPM" is an acronym for "Abnormal Spindle-like, Microcephaly-associated", which reflects its being an ortholog to the ''Drosophila melanogaster'' "abnormal spindle" (''asp'') gene. The expressed protein product of the asp gene is essential for normal mitotic spindle function in embryonic neuroblasts and regulation of neurogenesis. A new allele of ASPM arose sometime in the past 14,000 years (mean estimate 5,800 years), during the Holocene, it seems to have swept through muc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cerebral Cortex
The cerebral cortex, also known as the cerebral mantle, is the outer layer of neural tissue of the cerebrum of the brain in humans and other mammals. The cerebral cortex mostly consists of the six-layered neocortex, with just 10% consisting of allocortex. It is separated into two cortices, by the longitudinal fissure that divides the cerebrum into the left and right cerebral hemispheres. The two hemispheres are joined beneath the cortex by the corpus callosum. The cerebral cortex is the largest site of neural integration in the central nervous system. It plays a key role in attention, perception, awareness, thought, memory, language, and consciousness. The cerebral cortex is part of the brain responsible for cognition. In most mammals, apart from small mammals that have small brains, the cerebral cortex is folded, providing a greater surface area in the confined volume of the cranium. Apart from minimising brain and cranial volume, cortical folding is crucial for the brain ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cerebral Cortex
The cerebral cortex, also known as the cerebral mantle, is the outer layer of neural tissue of the cerebrum of the brain in humans and other mammals. The cerebral cortex mostly consists of the six-layered neocortex, with just 10% consisting of allocortex. It is separated into two cortices, by the longitudinal fissure that divides the cerebrum into the left and right cerebral hemispheres. The two hemispheres are joined beneath the cortex by the corpus callosum. The cerebral cortex is the largest site of neural integration in the central nervous system. It plays a key role in attention, perception, awareness, thought, memory, language, and consciousness. The cerebral cortex is part of the brain responsible for cognition. In most mammals, apart from small mammals that have small brains, the cerebral cortex is folded, providing a greater surface area in the confined volume of the cranium. Apart from minimising brain and cranial volume, cortical folding is crucial for the brain ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gene
In biology, the word gene (from , ; "...Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a basic unit of heredity and the molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protein-coding genes and noncoding genes. During gene expression, the DNA is first copied into RNA. The RNA can be directly functional or be the intermediate template for a protein that performs a function. The transmission of genes to an organism's offspring is the basis of the inheritance of phenotypic traits. These genes make up different DNA sequences called genotypes. Genotypes along with environmental and developmental factors determine what the phenotypes will be. Most biological traits are under the influence of polygenes (many different genes) as well as gen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Selective Sweep
In genetics, a selective sweep is the process through which a new beneficial mutation that increases its frequency and becomes fixed (i.e., reaches a frequency of 1) in the population leads to the reduction or elimination of genetic variation among nucleotide sequences that are near the mutation. In selective sweep, positive selection causes the new mutation to reach fixation so quickly that linked alleles can "hitchhike" and also become fixed. Overview A selective sweep can occur when a rare or previously non-existing allele that increases the fitness of the carrier (relative to other members of the population) increases rapidly in frequency due to natural selection. As the prevalence of such a beneficial allele increases, genetic variants that happen to be present on the genomic background (the DNA neighborhood) of the beneficial allele will also become more prevalent. This is called ''genetic hitchhiking''. A selective sweep due to a strongly selected allele, which arose on a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Evolutionary Pressure
Any cause that reduces or increases reproductive success in a portion of a population potentially exerts evolutionary pressure, selective pressure or selection pressure, driving natural selection. It is a quantitative description of the amount of change occurring in processes investigated by evolutionary biology, but the formal concept is often extended to other areas of research. In population genetics, selective pressure is usually expressed as a selection coefficient. Amino acids selective pressure It has been shown that putting an amino acid bio-synthesizing gene like ''HIS4'' gene under amino acid selective pressure in yeast causes enhancement of expression of adjacent genes which is due to the transcriptional co-regulation of two adjacent genes in Eukaryota. Antibiotic resistance Drug resistance in bacteria is an example of an outcome of natural selection. When a drug is used on a species of bacteria, those that cannot resist die and do not produce offspring, while th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tonal Language
Tone is the use of pitch in language to distinguish lexical or grammatical meaning – that is, to distinguish or to inflect words. All verbal languages use pitch to express emotional and other paralinguistic information and to convey emphasis, contrast and other such features in what is called intonation, but not all languages use tones to distinguish words or their inflections, analogously to consonants and vowels. Languages that have this feature are called tonal languages; the distinctive tone patterns of such a language are sometimes called tonemes, by analogy with ''phoneme''. Tonal languages are common in East and Southeast Asia, Africa, the Americas and the Pacific. Tonal languages are different from pitch-accent languages in that tonal languages can have each syllable with an independent tone whilst pitch-accent languages may have one syllable in a word or morpheme that is more prominent than the others. Mechanics Most languages use pitch as intonation to convey ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chromosome
A chromosome is a long DNA molecule with part or all of the genetic material of an organism. In most chromosomes the very long thin DNA fibers are coated with packaging proteins; in eukaryotic cells the most important of these proteins are the histones. These proteins, aided by chaperone proteins, bind to and condense the DNA molecule to maintain its integrity. These chromosomes display a complex three-dimensional structure, which plays a significant role in transcriptional regulation. Chromosomes are normally visible under a light microscope only during the metaphase of cell division (where all chromosomes are aligned in the center of the cell in their condensed form). Before this happens, each chromosome is duplicated ( S phase), and both copies are joined by a centromere, resulting either in an X-shaped structure (pictured above), if the centromere is located equatorially, or a two-arm structure, if the centromere is located distally. The joined copies are now called si ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
John Derbyshire
John Derbyshire (born 3 June 1945) is a British-born American far-right political commentator, writer, journalist and computer programmer. He was once known as a paleoconservative, until he was fired from the ''National Review'' in 2012 for writing an article for an online magazine that was widely viewed as racist. He now holds a staff position at the white supremacist website VDARE. In the article that caused his firing, Derbyshire suggested that white and Asian parents should talk to their children about the threats posed to their safety by black people. He also recommended that parents tell their children not to live in predominantly black communities. He included the line "If planning a trip to a beach or amusement park at some date, find out whether it is likely to be swamped with blacks on that date." He has also written for the ''New English Review''. His columns cover a broad range of political-cultural topics, including immigration, China, history, mathematics, and r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
