Gene Expression

Chinese propensity to copy

No, this isn’t about intellectual property issues and piracy. Whole Genome Distribution and Ethnic Differentiation of Copy Number Variation in Caucasian and Asian Populations:

Although copy number variation (CNV) has recently received much attention as a form of structure variation within the human genome, knowledge is still inadequate on fundamental CNV characteristics such as occurrence rate, genomic distribution and ethnic differentiation. In the present study, we used the Affymetrix GeneChip® Mapping 500K Array to discover and characterize CNVs in the human genome and to study ethnic differences of CNVs between Caucasians and Asians. Three thousand and nineteen CNVs, including 2381 CNVs in autosomes and 638 CNVs in X chromosome, from 985 Caucasian and 692 Asian individuals were identified, with a mean length of 296 kb. Among these CNVs, 190 had frequencies greater than 1% in at least one ethnic group, and 109 showed significant ethnic differences in frequencies (p<0.01). After merging overlapping CNVs, 1135 copy number variation regions (CNVRs), covering approximately 439 Mb (14.3%) of the human genome, were obtained. Our findings of ethnic differentiation of CNVs, along with the newly constructed CNV genomic map, extend our knowledge on the structural variation in the human genome and may furnish a basis for understanding the genomic differentiation of complex traits across ethnic groups.

Here’s a figure which shows the distributions, CHI = Chinese and CAU = Caucasion.*

i-bc1f61bfa9e0f77c45cc42baa2023293-cnvperperson.png

The big picture issue is CNVs may be important in gene expression, the paper cites a number that ~18% of the variance in this may be due to CNVs. An interesting recent case was CNV differences in regards to the gene which codes for amylase, with some researchers suggesting this is due to selection for the ability to digest starches for agriculturalists. In relation to the title, there might not be anything there:

A third example of ethnic variation is that the genomic coverage of CNVs in Asians is 1.6-fold higher than that in seen in Caucasians, indicating that genome variants were more common in Asians than in Caucasians. Further sensitivity analysis resulted in an only 1.2-fold elevated genomic coverage of Chinese CNVs compared to Caucasian CNVs. Considering different DNA extraction methods for Chinese and Caucasian samples, the ethnic differences seen in genomic coverage may be partially due to different binding affinities of diverse DNA extracts to the SNP chip array.

Citation: Li J, Yang T, Wang L, Yan H, Zhang Y, et al. 2009, Whole Genome Distribution and Ethnic Differentiation of Copy Number Variation in Caucasian and Asian Populations. PLoS ONE 4(11): e7958. doi:10.1371/journal.pone.0007958

* If they use “Caucasian” for European origin people, why not “Mongoloid” for Chinese?

Comments

  1. #1 bioIgnoramus
    November 21, 2009

    “If they use “Caucasian” for European origin people..”: I have assumed that to be a peculiarly American habit. Wrong?

  2. #2 Mark Houston
    November 21, 2009

    @Razib – If they use “Caucasian” for European origin people, why not “Mongoloid” for Chinese?

    My reaction: Exactly.

    Lets be honest, what does it really mean to be Chinese, if the whole idea of being Chinese refers to a people with a particular culture. I would like anyone, pre-19th Century, to show me a book, document, or a map, from the modern nation of China, which shows conclusively, that the idea of there being a Chinese race and nation, is as old as Persia, or Greece. Can this be done? I doubt it. The truth is that the idea of there being a Chinese people comes from Arab traders, who traded Ming porcelain with the Europeans. When the Europeans asked the Arabs where the porcelain came from, the Arabs replied: Cinni – ese people. Today, in the English language, we call the porcelain people, the “CHINESE.”

    Are the “Uyghur” ethnically Chinese. They are certainly not “Han”, since the Han were, once again, a culture, not an ethnic group. It really is time for a reality check for Chinese scientists. When it comes to modern Chinese ethnicity, there are only, northern mongolians and southern mongolians.

    Time to grow up.

  3. #3 Mark Houston
    November 22, 2009

    Thought I would add one more point. I have just opened my personal copy of “The Most Noble and Famous Travels of Marco Polo.”

    I have read Marco Polo’s book many times as a means of understanding 13th century Central & East Asia. Within this entire manuscript, which is backed by modern Chinese scholars, from Peking University, there is not a single mention of the words, China, or Chinese. Nor is there a mention of the Han ethnic group, which I find very strange. The manuscript does mention the Cataya (Cathay) people (Kitan Tartars), Mongols, Africa, Ethiopia, Russi (Russians), and even the Nestorian Christians. But, there is no mention of China or the Chinese.

    I have to ask. How is it possible for Marco Polo to miss the most dominant ethnic group of 13th Century East Asia, the Chinese.

  4. #4 Epistaxis
    November 22, 2009

    If they use “Caucasian” for European origin people, why not “Mongoloid” for Chinese?

    Probably because “mongoloid” used to refer to people with Down syndrome, on account of the epicanthal (or “mongoloid”) folds.

  5. #5 Shawn Lau
    November 22, 2009

    Mark Houston’s assertion that Chinese is culture identity not ethnic identity is silly. How do you define enthnicity? Is Jew an ethnic identity or religious identity? In reality, an ethnic group is a group of people under a common culture developed a common identity over the time – that is how racial or ethnic groups developed. We (people outside Africa) are all originated from a few thousands of Africans who wandered out the continent tens of thousands of years.

    I sense Mark Houston twisted an innocent scientific discovery to make some political statements.

  6. #6 deadpost
    November 22, 2009

    If they called it either “Caucasians and Mongoloids” or “Europeans and (East) Asians”, at least that would be consistent.

  7. #7 Utah
    November 23, 2009

    Mark Houston’s comment is nonsense on the point of ethinicity vs cultures. His effort to define Chinese as one ethic group shows his confusion about nations and ethinicities. Do Americans come with the same ethic group? No.

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