Genetics

Epigenetics studies heritable changes in gene activity that do not involve alterations to the DNA sequence itself. Methyl groups or proteins can attach to DNA and switch genes on or off. Studies on Dutch famine survivors (1944–45) found that their children and grandchildren showed altered metabolism and increased disease risk — showing that starvation changed gene expression patterns passed down across generations. This challenges the traditional view that only DNA sequence is inherited.

CRISPR-Cas9 is a molecular tool derived from a bacterial immune system that allows scientists to cut, edit, or silence specific genes with extraordinary precision. First harnessed for genome editing in 2012, it has since revolutionised biology and medicine. By 2023, the first CRISPR-based therapy (for sickle cell disease) was approved by the FDA. The tool works like molecular scissors guided by a RNA 'map' to the exact gene sequence needing editing.

Every human cell nucleus contains about 3.2 billion base pairs of DNA, distributed across 46 chromosomes. If fully stretched out end to end, the DNA from a single cell would measure approximately 2 metres. With roughly 37 trillion cells in the human body, your total DNA — laid end to end — would reach from Earth to the sun and back about 600 times. Despite this length, DNA is packed into a nucleus only about 6 micrometres wide through extraordinary coiling and protein scaffolding.

While seemingly disparate, this shared genetic material reflects common ancestry and fundamental biological processes essential for life. Many genes involved in basic cellular functions are highly conserved across diverse species.

While seemingly disparate, all living organisms share common evolutionary ancestors, leading to similarities in our genetic code. This percentage reflects the fundamental genes necessary for basic cellular functions that are conserved across diverse species.

Chromosomes exist in homologous pairs in diploid organisms, meaning the total count is typically an even number. Humans, for example, have 46 chromosomes (23 pairs).

The human body contains trillions of cells, each with about 2 meters of DNA tightly packed. If all the DNA from a single human were uncoiled, it would stretch from the Earth to the Sun and back over 600 times.

While this sounds astonishing, it primarily refers to the genes that govern basic cellular functions, such as metabolism and replication, which are highly conserved across many forms of life. This commonality highlights our shared evolutionary heritage.

Unlike most animals, octopuses frequently edit their RNA molecules, allowing them to fine-tune protein functions and adapt to environmental changes in real-time. This remarkable ability bypasses slower genetic mutation processes, contributing to their unique intelligence and survival.