Whether or not the story is true, the symbolism of the thistle (ahem, sorry for the pun) took root and is honored to this day. Other facts about the thistle include that it is a biennial plant, meaning it takes two years to complete its life cycle. It reseeds easily. It's a combination of beauty and ruggedness. It has a spreading, invasive root system, hence its classification as weed.
imprinted gene, a gene whose expression has been affected by genomic imprinting so that only a single allele functions, the other being turned off by epigenetic mechanisms during embryonic development.
The expression of a small number of human genes is influenced by whether the gene has been inherited from the mother or father. This process-called genomic (or parental) imprinting-usually means that the organism expresses one of its alleles but not both.In many cases the non-expressed allele is inactivated-for example, by DNA methylation. (High levels of DNA methylation are known to inhibit gene activity.).he expression of a small number of human genes is influenced by whether the gene has been inherited from the mother or father. This process-called genomic (or parental) imprinting-usually means that the organism expresses one of its alleles but not both.