遺傳度

出自維基百科,自由嘅百科全書
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早期嘅遺傳度研究想理解人嘅身高差異有幾多成係因遺傳而起嘅。

遺傳度粵拼wai4 cyun4 dou6英文heritability)係遺傳學同心理學等領域上常用嘅一個指標,用嚟量度一個表現型(phenotypic;一隻生物嘅某一個特定外形或者成份,例如係身高或者智能)特徵有幾受遺傳因素影響。遺傳度研究問嘅問題如下[1][2]

"What is the proportion of the variation in a given trait within a population that is not explained by the environment or random chance?"
「攞一個生物群體入面嘅一個特徵,個體之間喺呢個特徵上嘅差異有幾多唔係因為環境性或者隨機性差異而起嘅呢?」

遺傳度數值會喺 0 同 1 之間。遺傳度接近 0 就表示個體喺呢個特徵上嘅差異近乎完全係由環境因素而起嘅;而遺傳度接近 1 就表示個體喺呢個特徵上嘅差異近乎完全係由遺傳因素決定嘅,後者嘅例子有多種嘅遺傳病。而好多行為同心理上嘅特徵都會一定程度上受遺傳因素影響,例如大人嘅智商(IQ)嘅遺傳度估計超過 60% [3],噉係因為遺傳因素可以影響各部份嘅結構同特性,而腦嘅結構同特性就會影響行為[4]

遺傳度可以靠研究雙胞胎嚟估計:一對同卵性雙胞胎(identical twins)喺遺傳上近乎完全一樣,而一對異卵性雙胞胎(non-identical twins)喺遺傳上平均會有 50% 一樣;如果有一個特徵,同卵性雙胞胎喺呢個特徵上嘅差異細過異卵性雙胞胎嘅(假設每對雙胞胎都係喺同一個環境大,或者每對雙胞胎都係細細個分開咗),就表示呢個特徵會受遺傳因素影響。於是研究者就可以靠研究雙胞胎嚟估計一個特徵嘅遺傳度[5][6]

睇埋[編輯]

參考[編輯]

  • Lynch M, Walsh B (1998). Genetics and analysis of quantitative traits. Sunderland, Mass.: Sinauer Assoc. ISBN 978-0-87893-481-2.
  • Johnson W, Penke L, Spinath FM (2011). "Understanding Heritability: What it is and What it is Not". European Journal of Personality. 25 (4): 287–294. doi:10.1002/per.835. ISSN 0890-2070.

[編輯]

  1. Wray N, Visscher P (2008). "Estimating Trait Heritability". Nature Education. 1 (1): 29. Retrieved 24 July 2015.
  2. Kempthorne O (1957). An introduction to genetic statistics (1st ed.). Ames, Iowa: Iowa State Univ. Press.
  3. Panizzon, Matthew S., et al. "Genetic and environmental influences on general cognitive ability: Is g a valid latent construct?." Intelligence 43 (2014): 65-76.
  4. Trut, Lyudmila (1999). "Early Canid Domestication: The Farm-Fox Experiment". American Scientist. 87 (2): 160. doi:10.1511/1999.2.160. Archived from the original on 23 June 2011.
  5. Wahlsten, Douglas (1994). "The intelligence of heritability". Canadian Psychology. 35 (3): 244–260.
  6. Johnson, W., Turkheimer, E., Gottesman, I. I., & Bouchard Jr, T. J. (2009). Beyond heritability: Twin studies in behavioral research. Current directions in psychological science, 18(4), 217-220.

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