Spermatogenesis and fertility in Mus musculus as affected by factors at the T locus

Abstract

When animals of the same species are mated inter se it may usually be assumed that they will be fertile and that their progeny will be indicative of a random union of gametes. Dobrovolskaia-%am-adskaia and KoboxoefT ( '32) and later Koboziefl ( '35) have described t~7 0 mutations, t" and t', having ti11 apparent effect 011 segregation in the male mouse (Chcsley and Duiin, '36 ; Dunn and Gluecksohn-Schoenheimer, '39).Males heterozygous f o r either t" or tl transmit the mutation to their of'fspring with a frequency significantly greater than may be expected on an orthodox Mendelian basis.Both to and t' are at the locus of Brachy ( T ) , the factor for dominant short tail discovered by nobrovolskaia-Za~~~a~slrRia ( '27) and studied embryologically in the hcterozygous and lethal homozygous condition by Chesley ( '35). If t' is combined with T the resulting mice are tailless. When mated together T/tl animals (line 29) produce only tailless progeny through the operation of a system of balanced lethals as first described by Muller ( '18) in Drosophila. T/to (line A) mice are also tailless and true breeding. Males with normal tails (to/tl) may be obtained by crossing line A by line 29 and are com-'Submitted in partial fulfillment of the requirements for the degree of Doctor

Male Sterility in Mice Homozygous for the Tw2 Allele

“…Bryson (1943) and Braden and Gluecksohn-Waelsch (1958) found that the sperm from sterile genotypes (V/V, V/L, and L/L) had reduced motility, but they did not attach much importance to it. Bennett and Dunn (1967) found that the sterility of VMs/L genotypes was correlated with reduced motility and low numbers of sperm at the site of fertilization and not with reduced numbers inseminated.…”

“…However, the present results suggest that the sperm production of the sterile genotype t w2 t w2 is significantly reduced as judged by the numbers present in the vas deferens and in the uterus after mating. Bryson (1943) found a high proportion of morphologically abnormal sperm in the vas deferens of sterile (Lj L) males but felt this was insufficient to account for the sterility. Braden and Gluecksohn-W aelsch (1958) support these findings for they showed that some of the more fertile genotypes (V / V) produced a higher proportion of morphologically abnormal sperm than did the less fertile or sterile genotypes (V/L, L/L).…”

“…Subjective classifications (0, 1, 2, 3, and 4) were made of the relative numbers of sperm and their motility. One hundred sperm were selected at random and estimates of morphological abnormality made on a similar basis to that of Bryson (1943) and Rajasekarasetty (1954).…”

“…These combinations are as follows: (1) compounds of two different lethals, L/L (Bryson 1943;Braden and Gluecksohn-Waelsch 1958); (2) compounds of one lethal and one viable, L/V (Gluecksohn-Waelsch, Segal, and Fitch 1950;Rajasekarasetty 1954;Braden and Gluecksohn-Waelsch 1958); (3) compounds of two different or homozygous viables, V/V (Braden and Gluecksohn-Waelsch 1958); (4) compounds of one lethal and one viable male sterile, L/VMS (Bennett and Dunn 1967); (5) compounds of different or homozygous wild viable male steriles, VMS/VMS (Bennett and Dunn 1967). Although this latter type has been observed and the three alleles t W2 , t W8 , andt W36 have been found to be completely male sterile when homozygous, no detailed study has been carried out.…”

Interlitter variation in progeny of chimaeric male mice

“…Since evidence has been presented that (in some cases at least) males heterozygous for t produce equal quantities of t and non-r ( + or T) spermatozoa (Bryson, 1944 ;Yanagisawa, Pollard, Bennett, Dunn & Boyse, 1974), much interest has been shown in the nature of the two sperm types.…”