The first time we mate two hamsters together we get excited and each step along the way is full of excitement and awe.  First we introduce our two pet hamsters to each other and they meet there is a sense of hope and anxiety.  Hope that they will mate and offspring will follow but anxiety because we can't be sure that our two little bundles of happiness will turn on each other and one might damage the other beyond repair and we would have to live with ourselves having let such a fate happen to one in our care!!! Having tried to read up on all eventuallities and we find out that our female will be receptive every 4th evening then we feel less apprehensive and find out the cycle of our beloved female.  Then there is the hillarity of our tiny male trying to work out what his role in the business is, often trying the wrong part of the ladies anatomy.  Possibly after 2 or 3 attempts there is the sucessful mating followed by the long 16 days wait to see if it has been sucessful or not.  Then we have all heard stories (true ones) where eager people want to see the babies as soon as possible only for mum to feel threatened and consume each and every one of them.  So again there is the period of patience needed till we actually are allowed by mum (who will let you see them if she wants you to!).  We peer into the compact mass of babies attempting to count them.  After a period of just over a week we can start to make out the colours of the new born babes.  We start to wonder how such tiny things can possibly grow into adults having seen them in the pet shops at about 6 weeks old.  Gradually and amazingly in front of our eyes with each passing day they grow stronger and bigger.  They leave the nest, like old doddery folk stumbling into things.  Three weeks after birth they are quite sturdy and less dependent on mother and all sorts of colours!!!  How did that chocolate coloured one get there????

After sucessfully rehoming all the excess babies we consider breeding again.  By now our 2 pet hamsters has turned into 6!  The 2 we started with, the 2 babies we kept and the 2 new pets we just couldn't resist when we paid one of our visits to a pet shop to see what treats we could find.  So the 2 new ones are mated and we go through the whole process again - a little more confident and the patience seems a lot less of a strain.  This time there are a lot more different colours in the babies and again how did those surprises get there???  Well it's all about genetics.

We now start to wonder how to breed certain colours and we have been to a show or two and seen really good looking ones there so it must be possible!  We do more reading and find out that if we mate 2 black hamsters together then we will get a litter of all black hamsters.  
Genetics is the study of characteristics.  How do you get the required characteristic to show in your hamster?  Well it's all a matter of selection!  First you have to have the required characteristic in known hamsters and then by selectively breeding these to others that characteristic can be propagated to the offspring.  So starting with colour, which can readily be seen, then moving on to others required.

Colour genes:

The wild type Syrian hamster is golden in colour as this gives it the best adaptation in the wild.  Since the time that hamsters from the wild were first taken into captivity there have been several mutations creating different colours.  Commonly existing colours at present include 9 colour mutations in the syrian hamster.  6 recessive and 3 dominant colour mutations:
recessive colours include:
    black (a)
    rust (b)
    cinnamon (p)
    cream (e)
    dark grey (dg)
    white (cd)
dominant colours include:
    light grey (Lg)
    silver grey (Sg)
    yellow (To)

For the sake of simplicity consider the black gene.  To produce a black hamster we must start with a pair of hamsters carrying the black colour mutation gene.  Without this, then, barring a mutation, we cannot hope to produce the required black hamster.  Even with two hamsters carrying the black gene it is down to chance and other factors whether or not we end up with the black offspring!