Genes and chromosomes
Our bodies are made up of billions of cells. Most of the cells contain a complete set of tens of thousands of genes which act like a set of instructions, controlling our growth and development and how our bodies work.
Genes are carried on microscopically small, thread-like structures called chromosomes. There are usually 46 chromosomes, 23 inherited from our mother and 23 inherited from our father, so we have two sets of 23 chromosomes in ‘pairs’. Apart from two sex chromosomes (two Xs for a girl and an X and a Y for a boy) the chromosomes are numbered 1 to 22, generally from largest to smallest. People with an extra chromosome 8 usually have some cells with 46 chromosomes and others with 47 chromosomes (46 plus the extra chromosome). When cells with a different chromosome make-up exist alongside each other, the condition is known as mosaic. People with a small extra chromosome 8 are almost always mosaic. The degree of mosaicism can be different in every body tissue. So it can be different in the blood, the skin, the lungs, heart, brain and so on. Chromosome 8 is a medium-sized chromosome and contains 700-1,100 genes out of the total of 20,000 to 25,000 genes.
IN OTHER WORDS: Josephine is made up of all sorts of puzzle pieces, just as we all are. The only difference is that Josephine has two extra puzzle pieces that have nowhere to go, so they are just hanging out, maybe having a cup o’ joe waiting to figure out what’s gonna happen next…
