What is DNA

What is DNA?

Our DNA is the equivalent of two, almost identical, giant computer code/instructions that determines how our whole body, both develops and works. Half of this code/instructions you inherit from your Mum, the other half from your Dad.

 

What is a gene?

Using the same computer analogy our genes are small discreet parts of the giant computer code/instructions. We have approximately 44,000 such genes in most cells in our body, half of which (~22,000), we will inherit from our Mum and the other half (~22,000), we will inherit from our Dad. Each gene has the code/instructions, to make many differently shaped molecules called proteins. Most genes only make one such differently shaped protein, in a particular cell type, e.g. only in the sperm or the ovum (egg).

 

What is Whole exome sequencing (WES)?

WES is the sequencing of all of your 44,000 sequences. Fertility genomics can then analyse genes known to code for your sperm or ovum proteins, for any rare variations, that could significantly compromise your fertility.

 

How can an error in a single gene cause infertility?

If there is a single error/mistake (mutation) in the code/instructions in one such sperm or ovum specific gene, then this can cause fertility problems for the man or woman. Usually, however, we often get away with having only one normal and not two copies of the same sperm or ovum gene, without compromising a person’s fertility.

More commonly, either the woman or the man will unfortunately inherit two bad genes (one from the mother and one from the father), that both affect the same structural protein that is found either in the sperm or the egg. If this is the case, then either the mutated ovum will be unable to be fertilised by a normal sperm, or vice versa, i.e. a normal ovum will be unable or less likely to be fertilised by a sub-fertile sperm, by both normal and/or IVF conception.

In such cases, the direct sperm injection (ICSI) method can be a suitable alternative to achieve fertilisation, for affected couples. The good news, in such cases, is that children successfully born to such couples are highly unlikely to inherit any of their parent’s fertility problems. This is because such children are highly likely to inherit normal genes from the unaffected fertile parent and therefore only inherit one bad copy of the gene from the other sub-fertile parent.

In cases where mutations in sperm are likely to cause egg activation errors (i.e. the sperm does not “kick start” fertilisation) at ICSI. Artificial oocyte activation can be a way to compensate for the defective sperm function.

 

Assisted Reproductive Technology

As many as 12% of individuals will experience infertility1 , and an increasing number will turn to assisted reproductive technology (ART) for treatment. This term used to describe medical procedures which involve the in vitro (out of the body in a controlled laboratory environment) manipulation of sperm, eggs or embryos with the purpose of establishing pregnancy2. They are expensive, and the stakes are high as the procedures involve several complex steps. Incorrect consideration of factors which negatively impact the outcome of each step can result in failure.

 

The two main techniques that are used to achieve fertilisation are In Vitro Fertilisation (IVF) and Intracytoplasmic Sperm Injection (ICSI). For these techniques to succeed the sperm and egg must work properly. Fertility Genomics examines specific regions of your DNA which are necessary for producing normal functioning sperm and eggs (gametes), that are capable of coming together and fertilising.

 

The normal treatment pathway involves making the choice of IVF or ICSI. Knowledge of DNA errors which impact the gametes directly can give you an insight into the cause of your infertility and potential impact upon your ART procedure. Inform your decision making process by taking our “Fertility DNA” test.

 

  1. Datta et al., (2016). Prevalence of infertility and help seeking among 15 000 women and men. Human Reproduction. 31(9), 2108-2118. DOI: 1093/humrep/dew123
  2. Zegers‐Hochschild et al., (2009) The International Committee for Monitoring Assisted Reproductive Technology (ICMART) and the World Health Organization (WHO) Revised Glossary on ART Terminology. Human Reproduction. 24(11). 2683‐2687. DOI: 1016/j.fertnstert.2009.09.009
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What is DNA
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What is DNA
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