THE GENESIS OF LIFE

The steps that bring together DNA from parents and initiate pregnancy

FERTILISATION

For 12 to 24 hours after it’s released, an egg can be fertilised by a sperm cell that has successfully traversed the fallopian tube.

X MEETS Y, OR X

Following fertilisation, the two cells combine their DNA. Each cell carries a single copy of 23 chromosomes, which are large packages of DNA.

OVULATION

A mature egg cell, known as an ovum, is periodically released from a female’s ovaries as part of the menstrual cycle.

UNION

A fertilised cell with a full complement of 23 pairs of chromosomes forms a zygote, which migrates through the fallopian tube towards the uterus.

IMPLANTATION

The blastocyst adheres to the wall of the uterus, known as the endometrium, which helps nourish the embryo throughout its development.

CLEAVAGE

As the fertilised cell migrates towards the uterus it undergoes cleavage, dividing from a single cell into a connected cluster of cells called blastomeres.

MORULA

The berry-like configuration of blastomeres continues to divide, becoming a morula. During these latter divisions the cells commit to becoming either the embryo or placenta.

BLASTOCYST

A cavity of fluid builds between the inner cell mass, which will become the embryo, and the outer cells, which will help form the nourishing placenta.