How many copies of SINES are typically found in a human genome?

The correct choice indicates that there are over 1 million copies of SINEs (Short Interspersed Nuclear Elements) typically found in the human genome. SINEs are a type of transposable element and make up a significant portion of the human genome, accounting for about 10% of the total DNA. Notably, Alu elements, which are a type of SINE, are particularly abundant and can be found in vast numbers, contributing to the total count.

The estimated number of SINE copies is substantial because these elements can replicate and insert themselves at various locations throughout the genome, leading to a high frequency. Over time, SINEs have proliferated in the human genome through mechanisms such as retrotransposition, further increasing their presence.

While other choices suggest lower numbers, they do not accurately reflect the extensive presence of SINEs in the human genome. It is well-established in genomic studies that the population of SINEs is indeed over a million, aligning with the correct answer.