What's the difference between ancestress and foremother?

Ancestress

Definition:

Example Sentences:

(1) We describe the neuropsychological and behavioral profiles of 48 critical members of a previously reported Sardinian pedigree [Filippi et al., 1991], in which the fully manifested Martin-Bell syndrome (MBS), observed among males of the latest generations, is clearly the result of step-wise mutational events occurred repeatedly along the X-chromosome pathway linking all of them to a common ancestress, who must have been heterozygous for a fragile X (FRAX) premutation.
(2) This premutation appears to have turned into a true FRAX-mutation at least 9 times during the gametogenesis of the ancestress' X-related descendants of whom four are males.
(3) All the MBS patients and the 15 obligate heterozygous women present in the pedigree could be traced back through their X-chromosome lineage to the same ancestress, who must have been heterozygous for a silent premutation at the FRAX-locus.

Definition:

Example Sentences:

(1) We are facing a crisis in nursing not unlike that faced by our foremothers and forefathers: a shortage of nurses that promises to get worse before it gets better.
(2) We need to stop erasing the work of our foremothers.
(3) Going since the early 90s, Anne-kin is the foremother of all Scandinavian female detectives.
(4) As the writer Glosswitch has argued , the problem with the idea that feminism comes in waves is that “men get to leave something permanent; we seek to wash away the traces our foremothers left”.
(5) Morgan has chosen to reference his foremothers, but only very subtly.