A Probable Crossing Over or Mutation in the MNSs Blood Group System

Estimating the Recombination Frequency for the MN and the Ss Loci

“…This interval contains Gedde-Dahl's [1967] estimate for the recombination frac tion of 0.0032, even though his included all possible recombinants. When all possi ble recombinants in our data are used, the recombination frequency could range from 0.0033 to 0.0167 at the 96% confi dence level.…”

“…Studies have indicated that the MN and Ss blood group phenotypes are controlled by two closely linked loci with a small number of recombinations occurring be tween them [Gedde-Dahl et al, 1967;Chown et ai., 1965;Scholz and Murken, 1963). The question of interest is to deter mine accurately the frequency of recombi nation.…”

“…Chown et al [1965] reported 1 recombinant child out of 244 individuals, Il = 0.0041. Gedde-Dahl et al [1967], using published families, and the direct counting method, calculated a re combination fraction of 0.0032. This esti mate assumed that all possible cases of a recombinant gamete did represent such an event.…”

Reaction of the Human Anti-Gelatine Factor with Gelatine from Different Species and with Collagen Peptides

“…Crossing-over within the MN locus may have occurred; this has been reported a number of times, most recently by Gedde-Dahl [5], and seems not to be an extraordinarily rare event. The fact that the son does not possess the S, s, or the usual U antigen suggests another possibility, that he makes an altered or increased MN substance as a result of not making SsU Table I.…”

MNS Blood Group System

“…In one family an M − N + S − s + father and M + N + S + s + mother had three M − N + S − s + , three M + N + S + s + , and one M + N+ S − s + children [92] . Six other families are described in which MNSs inheritance anomalies could result from recombination [93] . Thus the mother appears to have passed Ns to three children, MS to three children, and Ms to another.…”