Abstract
This protocol combines a classical chromosome spreading technique with 3-dimensional image reconstruction for visualization of bivalent configurations during meiosis to aid chiasma counting.
Keywords: Chromosomes, Meiosis, Recombination, Chiasma, Maize
Background
Chiasmata are cytological manifestations of crossovers. Chiasma counting provides a fast and reliable assessment of meiotic recombination rates. Chiasmata are best quantified in maize at diakinesis in meiotic prophase I, as at this stage, they are most conspicuous. Advantages of cytological assessment of crossover rates are that it is fast, inexpensive, and can be performed on genetically homozygous individuals. This protocol improves on the classical chromosome spreading technique by combining it with modern 3-dimensional imaging, which improves the accuracy of chiasma counting, resulting in an error rate of 10% or less (Sidhu et al., 2015; Kianian et al., 2018).
Materials and reagents
Equipment
Procedure
Recipes
Acknowledgment
We thank Mateusz Zelkowski for pictures and video. Research to develop this protocol was supported by grants from the National Science Foundation (IOS-1025881 and IOS-1546792). This protocol was adapted from Sidhu et al. (2015). Authors declare no competing interests.
References
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