Cbo.org.uk

New research has shown how birds lost their penises over the course of evolution.

Birds such as chickens develop penises when they are embryos but only have basic organs as adults.

During the development of a bird they initiate a genetic programme that stop the budding penis from growing according to a study in Current Biology.

Co-author Dr Martin Cohn, from the University of Florida in Gainesville, said: “Our discovery shows that reduction of the penis during bird evolution occurred by activation of a normal mechanism of programmed cell death in a new location, the tip of the emerging penis.”

The team discovered a gene known as Bmp4 that when activated shrinks away the male genitals.

Since the males genitals are shrunk away they have to reproduce in another way and they do this by both birds touching each overs orifice which is also known as a cloaca and when the two touch the sperm from the male is transferred to the female.

Dr Cohn adds: ”Genitalia are affected by birth defects more than almost any other organ.

“Dissecting the molecular basis of the naturally occurring variation generated by evolution can lead to discoveries of new mechanisms of embryonic development, some of which are totally unexpected.

“This allows us to not only understand how evolution works but also gain new insights into possible causes of malformations.”

The academic studies, which show that mutated forms of the H5N1 virus could infect ferrets in aerosol form, provide the strongest suggestion yet that it could also be transmitted between humans.Fears over the deadly potential of the virus led the US National Science Advisory Board for Biosecurity (NSABB) to declare the work too dangerous to publish last year, and to recommend the papers be heavily censored before appearing in print.
In particular the revised paper clarifies that none of the ferrets which contracted the virus in its aerosol form had died – a fact which he admitted was not explicitly clear in the original version.Prof Paul Kein, chair of the NSABB, said that additional information from a confidential source about the possible risks and benefits of releasing the data had sparked the reversal of opinion.
H5N1 is mainly confined to birds but is often fatal when contracted by humans, and a variant which was transmissible from person to person via coughs and sneezes could prove catastrophic.