Your genes have a memory of which parent they came from

Gardening · Published 18 October 2026 Swipe more like this →

In short: Most of your genes are active, but some follow a strict rule: only one copy is allowed to speak. This process, called genomic imprinting, means certain genes are selectively silenced based solely on whether they were inherited from your mother or your father.

Genomic imprinting is an epigenetic phenomenon where the expression of a gene depends on its parental origin. Unlike standard Mendelian inheritance, which focuses on the DNA sequence itself, imprinting involves chemical modifications—specifically DNA methylation—that act as 'switches.' These marks are established in the germline (sperm or egg cells) and are erased and reset during gamete development before being passed to the next generation. This means that while you have two copies of most autosomal genes, only one copy is functional for specific roles.

These mechanisms are vital for regulating pre- and postnatal growth. Imprinting control regions (ICRs) maintain a delicate balance: some genes expressed from the paternal allele tend to promote growth, while those from the maternal allele often suppress it. For instance, the IGF2 gene is only expressed from the male-inherited allele. Because these switches are so precise, any disruption—whether through pathogenic variants, deletions, duplications, or uniparental disomy (inheriting both copies from one parent)—can lead to significant developmental, neurological, or metabolic disorders.

The consequences of 'mis-expression' are profound. In humans, more than 40 different regions are subject to imprinting. When these systems fail, it can result in syndromes like Angelman syndrome, caused by loss-of-function mutations in the maternally expressed UBE3A gene. This specific mutation leads to severe intellectual disability and a characteristic happy demeanor. Other disorders, such as Beckwith-Wiedemann syndrome or Prader-Willi syndrome, highlight how the precise dosage of parent-specific genes is fundamental to human biology.

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