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.
Genomic imprinting is an example of epigenetic inheritance in which differences in gene function depend on whether the allele was inherited from the mother or father. Many disorders appear to involve epigenetic alterations to imprinted genes. Genes involved in imprinting play important roles in both preâ and postânatal growth and neurodevelopment. Imprinting disorders include several childhood genetic disorders such as PraderâWilli, Angelman and BeckwithâWiedemann syndromes, as well as several types of cancer including Wilms tumour. Recent evidence suggests a correlation between assisted reproductive technologies (ART) and imprinting disorders, a phenomenon requiring more inâdepth studies as the prevalence of ART is increasing.