Genomes

Unity and diversity/Eukaryotic Genomes

genome

the entire set of DNA instructions found in a cell

What does the genome consist of in humans?

23 pairs of chromosomes

What does the genome contain all the information needed for?

an individual to develop and function

How is genome size measured?

in base pairs (bp)

What does genome size vary between?

different species

What varies between different species?

number of chromosomes hence the total amount of genetic material

What is the genome size between members of the same species usually?

the same

What is variation between members of the same species caused by?

changes in the base sequence of DNA

What is the diversity of genomes caused by?

variation in individual genes

Allele

alternative forms of a gene that differs only by a few bases

Single nucleotide polymorhpisms (SNPs)

alleles in which only one nucleotide within the sequence differs

Where can SNPs occur?

in coding and non-coding DNA

What does the existence of alleles make the genomes of the same species?

more diverse

What are alleles caused by?

different changes occuring to the DNA

What are these changes?

deletions, additions, insertions

What does a larger genome size mean?

that more functional genes are present

What is a lot of genetic material?

transposons (junk DNA)

What don't transposons have?

a known function

What do many plants have?

a bigger genome (shown in nucleotide pairs)

What is not always proportional?

genome size and the number of genes that are expressed