Transmission Ratios at the T-Locus in the Mouse: Inter-and Intra-Male Heterogeneity

Abstract

SummaryForty-nine litter series sired by Tt O , Ttl, Pt 3 , Tt 9 , Tt12, and Tt P' males of the house mouse were examined for heterogeneity of the transmission ratios of the l-allele. It was found that heterogeneity often I3xists, not only between males with the same t-allele, but even between litters from the same male; the latter was demonstrated by means of a new statistical technique. To measure the degree of heterogeneity, the mean square contingency was used as an index. It was found that intra-male heterogeneity was generally lower with "late" mating than with "normal" mating.It appears t,hat the behaviour in the female tract of spermatozoa carrying a t-allele differs from that of spermatozoa that do not have such an allele, and, further, that this behaviour is sensitive to slight variations in the physiological conditions in the tract.The statistical method used for examining the significance of the intra-male heterogeneity is described in an Appendix. It is a Monte Carlo method necessitating the use of an electronic computer. The method is useful in situations where cell frequencies are too low for the application ofaX2 test.

Autosomal trisomy syndromes: a detailed study of 27 cases of Edwards' syndrome and 27 cases of Patau's syndrome.

“…Work on the T-locus in the mouse (Braden and Weiler, 1964) has shown that the genotype of the egg may influence the sex of the sperm that is able to fertilize it. It may be that a similar type of gametic selection is operating in man, and that a disomic-18 egg is more readily fertilized by an Xbearing sperm.…”

Thein vivoandin vitrotransmission ratio distortion of one complete and two partialthaplotypes in mice

“…The decrease could, however, result from the total genetic background of either the male or the female since both have been shown to effect TRD (Braden & Weiler, 1964;McGrath & Hillman, 1980 a;Bennett et al 1983;Gummere et al 1986).…”

“…For example, the TRDs of some / haplotype bearing males are reduced when copulation occurs only 2 h before ovulation and fertilization (delayed matings). This is in contrast to the TRDs of the respective males when their spermatozoa reside in the female reproductive tract for 6-8 h prior to ovulation and fertilization (normal matings) (Braden, 1958(Braden, , 1972Yanagisawa et al 1961;Braden & Weiler, 1964;McGrath & Hillman, 1980a, b). Conversely, the TRDs of males bearing other / haplotypes are not affected by delayed matings (Yanagisawa et al 1961;Braden, 1972;Braden & Weiler, 1964;Garside & Hillman, 1989 a, b).…”

“…This is in contrast to the TRDs of the respective males when their spermatozoa reside in the female reproductive tract for 6-8 h prior to ovulation and fertilization (normal matings) (Braden, 1958(Braden, , 1972Yanagisawa et al 1961;Braden & Weiler, 1964;McGrath & Hillman, 1980a, b). Conversely, the TRDs of males bearing other / haplotypes are not affected by delayed matings (Yanagisawa et al 1961;Braden, 1972;Braden & Weiler, 1964;Garside & Hillman, 1989 a, b). Similarly, in vitro fertilization (IVF) may change the TRD of males bearing a specific / haplotype relative to its TRD during normal and/or delayed matings (McGrath & Hillman, 1980 a, b;Garside & Hillman, 19896), whereas the TRDs of males bearing other t haplotypes are not affected by this method of insemination (Garside & Hillman, 1989a).…”

Thein vivoandin vitrotransmission frequencies of thetw5-haplotype in mice

“…The frequency of transmission of these haplotypes is significantly reduced when insemination occurs in delayed matings or in vitro (McGrath & Hillman, 1980a, b). In addition, the study of Braden & Weiler (1964) and that of McGrath & Hillman (1980 a) show that the genotype of the female affects the frequency of transmission of these haplotypes. Based on these observations, McGrath & Hillman (1980 a) suggested that the expression of the aberrant transmission frequency is 'dependent on an interaction between the female reproductive tract and that this interaction is time dependent'.…”