SEX has baffled scientists for a long time because some of them wonder why it wouldn’t make more evolutionary sense if we all just asexually reproduced and made clones of ourselves like some plants and other animals do.
Now a group of researchers think they have the answer and have suggested that sexual reproduction is favoured by natural selection because it prevents the transmission of cancer.
2 The scientists put together this diagram showing how malignant cancer cells easily transfer in an asexual reproduction model (labelled A) but are less likely to in the sexual reproduction model (labelled B)Credit: Thomas F, Madsen T, Giraudeau M, Misse D, Hamede R, Vincze O, et al. (2019) Transmissible cancer an
Sexual reproduction is also said to provide other advantages over asexual like promoting important evolutionary advantages so a species can adapt to changing environments.
Multiple celled organisms emerged one billion years ago and since then sexual reproduction has helped to create and spread many cancer suppressing mechanisms in creatures, such as the human immune system, which can recognise cancerous cells from normal ones.
As asexual reproduction just results in offspring that are an exact copy of their parent, if the parent has cancer or a genetic disease then the offspring will do too.
Over time this could wipe out an entire species if diseases like cancer became extremely prominent and the creatures had no way of evolving a stronger immune system because they only had one set of genes.
2 Asexually reproduction is quite common in plantsCredit: Getty – Contributor
However, transmissible cancers in animals that sexually reproduce do still exist but they are very rare.
It is possible for a human mother to pass cancer cells directly to her baby and genetic evidence of a mother passing Leukaemia to her child was documented in 2009.
The researchers argue that sexual reproduction reduces this risk significantly though and see it as a novel explanation of why humans have sex.
This article has been published in the journal PLOS Biology.
What is asexual reproduction?Here’s what you need to know about the cloning method…
Asexual reproduction is when a single organism gives birth to an organism that is an exact clone of itself
The organism does not need a partner to do this as the genetic makeup of its offspring will just be exactly the same as its parent
This is the primary form of repoduction for single celled organisms like bacteria
Many plants and fungi reproduce asexually, as well as other creatures like starfish
We don’t know for sure why bigger multi-celled organisms like humans don’t reproduce asexually but current theories suggest that it has evolutionary purposes
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What do you think of this new sex theory? Let us know in the comments…
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