No single ‘gay gene’ & even clean tattoo needles can trigger allergic reactions

ScientiFix, our weekly feature, offers you a summary of the top global science stories of the week, with links to the best sources to read them.

Tattoo needles can trigger allergic reactions, research has shown | Commons

Study disproves existence of ‘single gay gene’

A vast study, conducted with data from over 500,000 individuals, has shown that no single gene can predict homosexuality. According to the report, sexual orientation is influenced by a multitude of genetic variants, with each having a tiny effect. The Guardian has more.

Tattoo needles can trigger allergic reactions

Scientists from the German Federal Institute for Risk Protection have found that tattoo needles can cause allergic reactions even when they are clean. Until now it was thought that tattoo inks — which contain high amounts of nickel, chromium, cobalt and mercury — were primarily responsible for these allergic reactions.

The research showed that titanium dioxide, a chemical used to brighten the colours of tattoo inks, erodes the needles, causing microscopic bits of chromium and nickel to enter the immune system. More on The New York Times.

3.8 million-year-old skull discovered in Ethiopia predates ‘Lucy’

Scientists have discovered a 3.8-million-year old skull that could reveal fresh insights into the origins of one of humanity’s most famous ancestors, Lucy. Researchers say this newly discovered species coexisted in prehistoric Ethiopia with Lucy’s species for at least 100,000 years. Nature has more.

SpaceX Starhopper completes final flight test

An early version of a spacecraft that SpaceX hopes will shuttle people into deep space one day completed its highest and most intense test earlier this week. The spacecraft, called Starhopper, fired up its engine for about a minute and soared 150 metres above the ground before landing upright. Starhopper has undergone a series of brief “hop tests” to collect data and help engineers understand how to land a spacecraft on another planet. SpaceX founder Elon Musk said that this was the last hop test for this prototype. More on CNN Business.

First-ever footage of Himalayan Monal’s mating dance captured in Uttarakhand

In a first, a video of a mating dance of a Himalayan Monal was captured at the Kedarnath Wildlife Sanctuary in Uttarakhand. A forest officer released the video of the colourful bird species, lophophorus impejanus, dancing in the wild. The officer said this may be the first-ever such footage from the Himalayan state. More on Hindustan Times.