polytene

adj

1. Having very large chromosomes with many chromatids (arms).

   “When this was done, it could be shown that the production of polytene chromosomes is not uniform for all chromosomes of a single nucleus, ie, some chromosomes are more polytene than others, […]”

noun

1. A very large chromosome with many chromatids (arms); a chromosome exhibiting polyteny

   “Unlike normal chromosomes, polytenes are visible in a microscope even when cell division is not taking place.”