Fig. 5

Various resolution patterns can lead to different DNA meiotic recombination events. a Meiosis I spindles begin to pull maternal and paternal chromosomes in opposite directions before both the HJs are resected. Thus, topologically, the dHJ is resolved and 2 symmetric heteroduplexes are generated. After subsequent mitosis, post-meiotic segregation occurs, displaying aberrant 4:4 segregation. b Resolution of 2 junctions by cutting inner, crossed strands leads to crossover of genes between 2 HJs. c Resolution of 2 junctions by cutting outer, noncrossed strands does not impact the products after repair synthesis. d Compared to (b), opposite-sense cutting, e.g., in the left-hand HJ, the crossed strands are cut, and in the right-hand HJ, the noncrossed strands are cut, generates crossover containing upstream regions. e Cuts are made on strand 1 and strand three in both HJs. After the pull of meiosis I spindle, 2 duplexes form, each of which contains a single-strand gap. Both gaps are subsequently repaired by repair synthesis, leading to gene conversion (6:2 segregation). f Cuts are made on strand 1, 2, and 3 in both HJs. After the pull and repair synthesis, the information on black chromatid is transferred to the homologous region of the red one. The original information on the black chromatid is deleted, leading to gene conversion of deletion. g Cuts are made on strand 1 in both HJs. The resolution generates a duplex with a single-strand gap and another duplex with a 3-stranded region. Within the 3-stranded region, there first is a duplex composed of strand 1 and strand 3. Then, the duplex interacts with strand 4, forming a 3-stranded DNA. After mitosis, the 3-stranded helical DNA results in post-meiotic segregation, displaying normal 5:3 segregation. h Contrary to (g), cuts are made on strand 2 in both HJs. Post-meiotic segregation also arises, but the products display aberrant 5:3 segregation. i When cuts are made on strand 1 and 2 in both HJs, the information on black chromatid would be deleted and transferred to the red one. Then, a 4-strand helical DNA composed of 2 duplexes appears. After mitosis, the 4-strand helical DNA can also result in post-meiotic segregation