Karyotype and genome evolution in pteridophytes

Although genomics is a field often discussed as a recent development brought upon by the advent of next-generation sequencing technologies, the roots of genomics extend to at least the early twentieth century. Rather than running a gel or assembling sequence reads on a server, early cytologists squashed and stained actively dividing cells and viewed them under a microscope to reveal a variety of chromosome features including numbers, sizes, and pairing behavior. These data revolutionized our perspective of plant species, and provoked numerous questions about genome evolution, some of which endure today. Among these long-standing questions is how the high chromosome numbers of homosporous ferns and lycophytes evolved and are maintained.