Allometric genetics and linkages of teosinte characters in 4S --Luiz Eugenio Coelho de Miranda and Luiz Torres de Miranda W. C. Galinat (MNL 49:102) reported linkages of two new genes, Ph and Ri. The recombinational distances were Ph--27--Ri--39--Su--20--Gl3. Taking Ph as the 0 (zero) position su1, the reference gene, was put in position 66=(27+39). Transforming the p values into Haldane's centimorgans we would have Ph--31--Ri--50--Su--22--Gl3, with Su in the 81 position. We think this is not the most probable position. Taking Haldane values and obtaining the new values, appropriately paired, we use all six values of cM for the estimates; thus with the original data the distance Su Gl3 is obtained as:

Ph Gl3 45 66.0 - Ph Su 43 59.6 = Su Gl3 6.4

Ri Gl3 40 52.2 - RiSu 39 50.0 = Su Gl3 2.2


And with the same procedure Ri Su=29.8±1.7 and Ph Ri=11.7±2.0, which leads to Su in position 41.5. Calculating p by the product moment method we arrive at Ph--10.6--Ri--30.7--Su--4.2--Gl3 and Su1 would be in position 41.3 with Ph at the zero position. The new value cM=4.2-4.3 for Su Gl3 strikingly brings out the proposed interference of a heterozygous inversion; it would be Su Gl3 p=0.34 with cM=42.6 without interference. This fact could be used to quantify inversion and translocation effects by developing a theoretical model. The new rearrangement also would bring to closer position the teosinte factors pd4 and tr4, which we proposed (MNL 61:32-34) to be in positions 3 and 7 respectively considering Ts5 to be in 53 position.

Please Note: Notes submitted to the Maize Genetics Cooperation Newsletter may be cited only with consent of the authors

Return to the MNL 63 On-Line Index
Return to the Maize Newsletter Index
Return to the Maize Genome Database Page