• Question: whenever you are pregnant, how does your body know how to create a baby inside you with exactly 2 eyes,2 ears, lungs etc ??

    Asked by itz_elanaboyd to David, Gemma, Juhi, Matt, Stéphane, Yinka on 8 Mar 2018.
    • Photo: Juhi Gupta

      Juhi Gupta answered on 8 Mar 2018:

      This is all down to our genes! Our DNA contains the genes that produce the correct molecules that signal to our body exactly how our physical make-up should be. Small differences in the bases of our DNA can lead to difference such as differences in eye colour etc. When it comes to development, it is not just a matter of one or two genes, but many genes interact with each other in a network that is carefully regulated when a foetus is developing, so that the correct number of organs are formed. If there an error in the DNA right at the beginning then this is not likely to replicate into another cell and is cleared away by the body’s internal DNA clearing system.

    • Photo: Stéphane Berneau

      Stéphane Berneau answered on 8 Mar 2018:

      Hi,

      Very interesting question… my area of research 😉
      Whenever you are pregnant, early on your body recognise signs of an egg being fertilised and the embryo will implant and grows as a foetus and other extra-embryonic organs such as the placenta.
      In normal condition, the mother body cannot influence the development of morphological organs. The orientation of development is regulated by the expression of specific genes called Homeobox (highly conserved between species). Once the orientation is in place, regulation of another will allow the development of foetus. Nothing to do with genes regulation about hair colour, eye colour… “Everybody” has the same genes for the development. Of course, issue can happen leading to a defect in development.
      Nice little video about development

      If you want more details, do not hesitate.

    • Photo: Gemma Chandratillake

      Gemma Chandratillake answered on 9 Mar 2018:

      The instructions for the baby’s development are in the genes of the baby (known as an embryo at this point). The genes are contained in a chemical called DNA that is found in each cell. For most embryos that grow into babies that are born and survive, these instructions work just fine, but sometimes there can be glitches in the instructions that cause developmental problems in the baby, or something else that causes the instructions not to be followed properly. This can lead to miscarriage and is also why some babies are born with birth defects, or “congenital anomalies”, which is why people have ultrasound scanning in pregnancy (https://www.nhs.uk/conditions/pregnancy-and-baby/anomaly-scan-18-19-20-21-weeks-pregnant/).
      The process of growing a new person is so amazingly complicated that it is not surprising that it sometimes goes a bit awry – about 1 baby in 50 is born with some aspect of their body looking a bit different (some things can seriously affect their health like heart defects, some are less serious like an underdeveloped ear, or a cleft lip). It is important to realise that these things just happen, usually can’t be prevented, and aren’t anyone’s fault so that we can make sure to have a society that takes care of everyone fairly.

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