Worm Breeder's Gazette 17(3): 28 (November 1, 2003)

These abstracts should not be cited in bibliographies. Material contained herein should be treated as personal communication and should be cited as such only with the consent of the author.

Stanford males are still the greatest!

Jonathan Hodgkin, Aline Kuhl

Genetics Unit, Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK

In previous investigations of male fertility in different wild isolates of C. elegans, it was found that males from the Stanford race CB4855 are substantially more fertile than males from the standard Bristol race N2 (Hodgkin and Doniach (1997), Genetics 146: 149-164).  More recently, several investigators have observed that the Hawaiian race CB4856 also exhibits high male fertility, so that male plates can be maintained indefinitely, simply by chunking rather than by setting up new crosses periodically (Hammarlund & Jorgensen (2001), wbg17.1p38).


We were curious as to whether high male fertility occurred in any other wild isolates.  We therefore tested 6 - 12 individual males from a set of 11 geographically assorted races for the ability to sire progeny after more than three days of adult growth at 20 degrees C.  Males were tested by daily transfer to fresh plates containing six young adult fem-1(hc17ts) females, as described (Hodgkin and Doniach, 1997).  The races examined were: N2 (Bri), CB4855 (Sta), CB4856 (Haw), AB1 (Ado), AB3 (Adt), RC301 (Fre), CB4932 (Tau), CB4857 (Cla), CB4854 (Gan), CB4853 (Gat), DH424 (Epc).


The table below reports the fractions of males capable of siring progeny on days 3 - 10 of adulthood. We confirmed long-term fertility for CB4855 (Sta) and CB4856 (Haw).  The only other race in this set that exhibited comparable endurance was the Adelelaide race AB1 (Ado).

Rough estimates of total progeny sired at late time points suggest that CB4855 (Sta) has the highest male fertility of these three races, and AB1 (Ado) the lowest.


Other races appear similar to or slightly more fertile than N2 in this survey, which is admittedly superficial.  The Californian Epc (DH424) race appears less fertile, perhaps because this strain carries a high Tc1 transposon load. Very high Tc1 loads, as in the Bergerac strains CB4851 and RW7000, are associated with effectively complete male infertility.  The Vancouver race KR314 also exhibits male infertility, as a result of homozygosity for a mab-23 mutation.  Overall, we tentatively conclude that high male fertility is the exception rather than the rule, among different wild populations of C. elegans.


            Day     3          4          5          6          7          8          9          10


Bri                   10/10   3/10     0/10

Sta                   10/10   10/10   9/10     8/10     8/10     3/10     1/10     0/10

Haw                10/10   7/10     4/10     3/10     3/10     2/10     0/10

Ado                 12/12   12/12   11/12   8/12     6/12     3/12     1/12     0/12

Adt                  10/10   5/10     0/10

Fre                   10/10   2/10     1/10     1/10     0/10

Tau                  10/10   3/10     0/10

Cla                   6/6       6/6       3/6       1/6       1/6       0/6

Gan                 6/6       5/6       3/6       2/6       1/6       0/6

Gat                  4/6       3/6       2/6       1/6       1/6       1/6       0/6

Epc                  6/12     2/12     0/12