Male fish mutating into females because of waste chemicals, expert warns

Expert calls for stronger stance on chemicals and drugs that are likely to have ‘sub-lethal’ effects on wildlife

Ian Johnston Environment Correspondent

Monday 3 July 2017 13:00 BST

Tougher controls should be considered on chemicals that can feminise male fish and cause other “sub-lethal” effects, a leading ecotoxicologist has said.

Nearly 10 years after he helped reveal how significant an impact human drugs were having on wildlife, Professor Charles Tyler has warned that scientists are becoming increasingly concerned about the consequences of thousands of waste substances.

Some are from industrial processes, but others are drugs taken by people that then pass through them and into the sewers or are simply flushed directly into the toilet.

Professor Tyler, of Exeter University, will talk about the issue in a speech at the 50th Anniversary Symposium of the Fisheries Society in the British Isles.

He took part in a major study in 2008 that found nearly a quarter of male roach fish taken from 51 sites on English rivers showed signs of becoming female, such as having eggs in their testicles.

In some rivers, all the male roach were found to have been feminised to a degree because of high levels of oestrogen, which is used along with progestin in birth-control pills to prevent ovulation and is also present in other drugs.

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Scientists identify mutation that causes muffs and beards to grow on chickens

June 2, 2016

The growth of long facial feathers, creating the appearance of muffs and beards on chickens, is caused by a chromosomal rearrangement affecting a gene involved in feather development, report Xiaoxiang Hu of the China Agricultural University in Beijing and colleagues, in a new study published on June 2 in PLOS Genetics.

Unusual plumage and fancy combs aren't just interesting traits appreciated by poultry fanciers, but opportunities to explore the genetics underlying these striking variations. Scientists investigated the mutation that causes the Muffs and beard characteristic in certain chicken varieties by mapping the trait to the correct location on the chromosome and sequencing that region from chickens with and without Muffs and beard. They found that chickens with the Muffs and beard trait had three duplicated regions of chromosome 27, inserted next to one of the original gene regions. By examining changes in gene expression, they showed that one of the duplicated genes, HOXB8, which is known to function in feather development, was present at high levels in the facial skin of chickens with Muffs and beard, but not in regular chickens.

The scientists suspect that HOXB8 expression may extend the growth phase of the facial feathers, creating the characteristic bearded appearance. Other HOX gene members are linked to feather development, such as HOXC8, which is associated with a crest of feathers on top of the head. The findings present an excellent model for exploring the regulation of HOX genes in different parts of the body during development.

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Famous peppered moth's dark secret revealed

By Jonathan Webb Science reporter, BBC News

1 June 2016

Scientists have discovered the specific mutation that famously turned moths black during the Industrial Revolution.

In an iconic evolutionary case study, a black form of the peppered moth rapidly took over in industrial parts of the UK during the 1800s, as soot blackened the tree trunks and walls of its habitat.

Now, researchers from the University of Liverpool have pinpointed the genetic change that caused this adaptation.

They have also calculated the most likely date for the mutation - 1819.

Their study appears in the journal Nature, alongside a second paper, which describes how the same gene allows tropical butterflies to switch between different colour schemes.

Dr Ilik Saccheri has been working on the peppered moth since setting up his Liverpool laboratory 15 years ago, he told Science in Action on the BBC World Service.

"When I started working on it I was surprised, given how well known it is, that no-one had actually tried to... characterise the underlying genetics controlling the physical appearance of this moth," he said.

"It's a graphic example of rapid evolutionary change. In the days before we could track mutation and change in bacteria and viruses, there weren't many examples of visible change within a human lifetime."

And it was indeed an early discovery; black moths, strikingly different from the insect's usual mottled white, were first spotted in 1848 - 10 years before the concept of natural selection was formally outlined by Darwin and Wallace.

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