A naked look inside the nucleus at the chromosomes… (Day 60)

Human Chromosome Genetics Microscope

Another Friday, Milk hygiene today was looking at the properties of tinned milk and condensed milk. I am now at the stage where I feel like I know more about milk than any single sane person would ever want to. Some of its useful, some not so useful, and then theres the plain interesting such as how many tests are carried out. Some of its scientific such as the massive list of potential bacterias, and then theres the not so scientific such as the “Cooked Taste” that steralised milk has.

Now genetics today we started looking at the Chromosomes that basically contain the code for all living things. Its amazing how something so small can determine whether you are male or female, in fact determine everything about you. Now lets make it a little more interesting, this is what you look like when everything else is stripped away…

Human Chromosome Genetics Microscope
The Chromosomes from the nucleus of a human cell… Yes, this is what we look like inside!

Now obviously this cell nucleus has been increased, this is done by using a hypotonic solution which causes the cells to swell whilst leaving the centromeres intact. This allows you to view the chromosomes under a normal light microscope as above (this image is at 1000x magnification if I remember correctly).

When examining the chromosomes we use something called the karyotype which is unique to each animal species (the number of chromosomes is different between species too). Basically the different chromosomes are arranged on different rows representing groups based on shape, size and where their center is. Using this it is then possible to identify the species, and even determine whether it is male or female from looking at the sex chromosomes. Here are the chromosomes from a Rat…

The chromosomes from a Rat in Genetics
Rat Chromosomes under the microscope

And here are the chromosomes from cattle (cows/bulls etc), if you click on the picture you can see a bigger version as well! 🙂

Cattle Chromosomes under the microscope in Genetics
Cattle Chromosomes under the microscope

A few weeks ago you may remember me talking about the bone marrow and how it was harvested from the femur of the mouse. We came back to it this week in addition to the bone marrow and blood collected from the cow. Today we prepared these for microscopic examination removing them from the solution and staining them (they are not naturally pink/purple) onto slides.

Histology Blood and Bone Marrow Stained Slides
Blood and Bone Marrow slides prepared for the microscope

These then were examined under the microscope, and I did actually find a cell in the metaphase stage of mitosis in the bone marrow I collected from the mouse! Looks pretty cool right (the small circle of purple chromosomes)? Amazing how something so small can control something so complicated…

My mouse chromosome in metaphase stage of mitosis
Mouse chromosome in Metaphase stage of mitosis

Hopefully you have enjoyed todays diary as much as me! Now I really must sleep, Friday always is so long, and by the end I am always so exhausted I think it is because the week catches up with me.

Bone Marrow and the Chromosome (Day 32)

Post Mortem Bone Marrow Collection

Its the end of my 4th week of Vet School already! Time is flying by which is kind of Scary as I am still a long way from having tuition for next semester in February and its under 4 months away now! I’ve made plans to revamp my money raising stragety this weekend and am toying with a few ideas.

The lecture this morning overran into the time allocated for our Milk Hygiene practical which was a little sad. Today was on the microbiology of milk which is a little scary when you start to think how much milk is actually used in different ways and then just how many bacteria it is susceptable to.

Onto Genetics practical, this week we are looking at the chromosome and karyotyping, this practical session was on the examination of these from the bone marrow.

Post Mortem Bone Marrow CollectionThere are two ways to collect bone marrow depending on the species, today was on the post mortem collection and was from the femur of a mouse. This type of animal is too small to allow for collection of bone marrow in any other way and so after euthanasia the femur was removed, and the marrow cavity exposed. This was then rinsed out to collect the cells of the bone marrow which were then centrifuged and the supernatant removed to leave just the cells in the tube before staining solution was applied. This does have to be left for some time so we are coming back to examine these at another time. I will also write an entire post on the Chromosome at somepoint in the next week or so as we are looking at this over the entire next few weeks.