gene + environment + triggers + chance = phenotype 基因+环境+触发+概率=表型

Know then thyself, presume not God to scan;
The proper study of mankind is man.
— Alexander Pope, Essay on Man


Several genome‐wide association studies (GWAS) [1-13] have been reported and provide evidence for over 40 genes involved in psoriasis causation (Table 1. Psoriasis susceptibility genes and their function).

Table 1. Psoriasis susceptibility genes and their function
gene table

In humans, a mutant Table 1. gene increases the risk for psoriasis — but not all people carrying the Table 1. gene mutation develop psoriasis. As we know currently, even if the gene(s) (Table 1) is/are inherited, psoriasis is not absolutely presented as its capacity to become expressed into an actual attribute varies from one individual to another.


Examination of twins has shown concordance for psoriasis in 20% of monozygotic twins compared to 9% for dizygotic twins, corresponding to an estimated heritability of 68% [14-16] . (Monozygotic twins, who are truly genetically identical, are derived from the splitting of a single fertilized egg; dizygotic twins, who are merely genetic siblings, are derived from the simultaneous fertilization of two eggs by two sperm).

For instance, one person with the Table 1. gene(s) mutation might develop an severe generalized pustular psoriasis. Another with the same mutation might develop an plaque psoriasis; and yet another might not develop psoriasis at all.

We still do not know what causes the difference of outcomes between these three person — is it some combination of age, exposures, other genes, and bad luck? You cannot use just the Table 1 genotype mutation to predict the final outcome with certainty.

phenotype (disorder) = genotype (gene) + environment + triggers + chance (luck)

The above formula [17] may captured the essence of the interactions between heredity, chance, environment, variation, and evolution in determining the form and fate of an organism.


How do genes interact with environment, triggers, chances to cause order versus disorder? For that matter, what is order versus disorder? How do the variations in genes cause variations in human form and function? How do multiple genes influence a single outcome? How can there be so much uniformity among humans, yet such diversity? How can the variants in genes sustain a common physiology, yet also produce unique pathologies? What we known is just a drop in the ocean.




在人类基因组关联研究(GWAS)中[1-13],有40多种基因突变会增加罹患乳银屑病(牛皮癣)的风险(表1. 银屑病基因及其功能)。表1的突变基因增加了银屑病的风险 — 但并非所有携带表1基因的人都会罹患银屑病。我们目前知道,即使基因(表1)已被遗传,银屑病也并非绝对对应出现,因为其表达为实际属性的能力因人而异。


对双胞胎的研究显示,单卵双胞胎中有20%患有银屑病,而双卵双生子中只有9%,遗传力估算值为68%[14-16]。 (单卵双胞胎在遗传基因上是完全相同的,是从单个受精卵分裂而来;双卵双胞胎,仅是遗传基因相似,是由两个精子同时受精两个卵而得)。


表型(失调)= 基因+环境+触发+随机概率






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