GENETICS

Genes Live on Chromosomes

1902 to 1915 CE

Phanerozoic · Cenozoic · Quaternary · Holocene · Meghalayan

Mendel's abstract units were given a physical address. Chromosomes pair up, separate and get dealt out in exactly the way inherited factors behave, which was noticed in 1902. It stayed an analogy until a white-eyed fruit fly turned up in a Columbia laboratory and its trait was seen travelling with the chromosome that determines sex.

Why it matters

Heredity stopped being a statistical rule and became an object: something that sits in a particular place, on a particular thread, and can therefore be mapped. Everything that follows in this part of the timeline, from the double helix to genome editing, depends on the gene having a location.

Dating & uncertainty

Sutton and Boveri proposed the link in 1902 and 1903; it was contested until the fruit fly work of 1910 to 1915 tied specific traits to specific chromosomes.

Sources

1. Crow & Crow (2002), Genetics · 100 years ago: Walter Sutton and the chromosome theory of heredity
2. Morgan (1910), Science · Sex limited inheritance in Drosophila
3. Carlson (2013), Mutation Research · How fruit flies came to launch the chromosome theory of heredity

Earth history as one day

23:59:59.99762.4 ms before midnight

if Earth’s 4.54 billion years were compressed into a single day