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You have 46 chromosomes. Each chromosome is one massive contiguous molecule of DNA, which can be represented as a string of (up to) 150 million letters ("nucleotides") drawn from {A, C, G, T}. Together, the whole human genome is roughly 3 billion nucleotides. Since you have two copies in each cell, you have 6 billion nucleotides in total.

Each chromosome is either an autosome or sex chromosome. The autosomes are chr1 to chr22. All people (excepting those with chromosomal disorders, like trisomy 21) have two copies of each autosome, with one copy coming from each parent. Then, for the sex chromosomes:

* If you're male, you get an X chromosome from your mom and a Y chromosome from your dad.

* If you're female, you get an X chromosome from your mom and another X chromosome from your dad.

So, yes, "two copies of each chromosome" and "two copies of the genome" are the same concept, since the genome consists of chromosomes.



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