You will be shown an abstract from a biomedical research paper. Given this abstract, your task is to extract all unique entities of the following types: ["AnatomicalEntity"].

Please return the output as a JSON object of the format: {"AnatomicalEntity": ["tumor cells", ...]}. The keys should be entity types and values should be lists of extracted entities belonging to the corresponding type. If you cannot find entities belonging to a specific type, the value should be [].

Only output the JSON object and do not include any additional text.

Abstract:

Background
Over the past decades, extensive comparative mapping research has been performed in the plant family Solanaceae. The recent identification of a large set of single-copy conserved orthologous (COSII) markers has greatly accelerated comparative mapping studies among major solanaceous species including tomato, potato, eggplant, pepper and diploid Nicotiana species (as well as tetraploid tobacco). The large amount of comparative data now available for these species provides the opportunity to describe the overall patterns of chromosomal evolution in this important plant family. The results of this investigation are described herein.
{"AnatomicalEntity": ["chromosomal"]}