Shot of genome recorded in a bound book following human genome project

Male and female genomes

We inherit a complete genome from our mother and another from our father

Every person’s genome is different, so the one we inherit from our father is not the same as the one we inherit from our mother – and it even appears that genomes may be engaged in a genetic ‘tug of war’ within a developing embryo.

It has been discovered that chemical modifications to DNA can be stably passed on when a cell divides. This ‘imprinting’ process controls whether a gene is active or not.

An example of parental imprinting is the insulin-like growth factor system, which has a strong influence on the size of a baby. The logic is that the genome inherited from the father works to maximise the growth of the offspring, to give it the best chance of survival when it is born. The maternally inherited genome, though, limits the size of the offspring and protects the mother, so she can go through further pregnancies.

So parents’ genomes may be constantly battling with one another, driven by evolutionary pressures to ensure that their DNA survives and spreads.

However, in each newly fertilised egg there is another form of DNA – mitochondrial DNA. Mitochondrial DNA is inherited directly from the mother, without any mixing or shuffling, and is housed in energy-producing powerhouses in the cell called mitochondria. This means that in each of our cells we keep a record of our grandmother’s genome, and her grandmother’s genome, and so on and so on, all the way back through time along the maternal line.

Lead image:

Adam Nieman/Flickr CC BY

References

Further reading

About this resource

This resource was first published in ‘Sex and Gender’ in January 2006 and reviewed and updated in October 2014.

Topics:
Cell biology, Genetics and genomics
Issue:
Sex and Gender
Education levels:
16–19, Continuing professional development