Table 3.
Physical (in millions of base pairs, Mb) and genetic distances (in centimorgans, cM) that were covered by the largest linkage group in each chromosome, by species
| L subgenome | S subgenome | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Species | Sex | Mb | cM | cM/Mb | F/M cM/Mb ratio | Mb | cM | cM/Mb | F/M cM/Mb ratio | Mb | cM | cM/Mb | F/M cM/Mb fm ratio |
| X. tropicalis | F | 1401 | 1191 | 0.85 (0.07) | 1.32a | ND | ND | ND | ND | ND | ND | ND | ND |
| M | 1342 | 867 | 0.65 (0.12) | ND | ND | ND | ND | ND | ND | ND | ND | ||
| X. laevis | F | 2450 | 1964 | 0.80 (0.08) | 1.50a | 1355 | 992 | 0.73 (0.05) | 1.31a | 1095 | 973 | 0.89 (0.16) | 1.75 |
| M | 2549 | 1367 | 0.54 (0.04) | 1405 | 785 | 0.56 (0.05) | 1144 | 582 | 0.51 (0.07) | ||||
| X. borealis | F | 2324 | 1739 | 0.75 (0.07) | 2.66a | 1261 | 910 | 0.72 (0.12) | 3.07a | 1063 | 829 | 0.78 (0.09) | 2.29a |
| M | 2402 | 675 | 0.28 (0.04) | 1342 | 315 | 0.23 (0.03) | 1060 | 360 | 0.34 (0.07) | ||||
ND - Not Defined.
The ratio of these distances (cM/Mb) and the female:male ratio of these ratios (F/M cM/Mb ratio) allows for comparisons of the average genome-wide recombination rate during oogenesis (F) and spermatogenesis (M). These statistics were also calculated for the L and S subgenomes (L and S subgenome, respectively) of the allotetraploids X. laevis and X. borealis. The weighted standard error of the mean is given in the parentheses. aSignificant departure of the F/M cM/Mb ratio from the null expectation of no bias (see Materials and Methods).