Such loop might cover about 2/3 of the bivalent length due to lack of synapsis of acrocentric and submetacentric homologues, which might be easily identified in hybrids, using an electron microscope or fluorescent microscope and immunostaining for SYCP3 (synaptonemal complex protein 3) and CREST (Calcinosis Raynaud’s phenomenon, Esophageal dysmotility, Sclerodactyly, and Telangiectasia) for a centromere region of chromosomes. Here, SS18L1 is linked to telangiectasis.