The genetic structure of 26 natural populations of three species (S. tridecemlineatus, S. mexicanus, and S. spilosoma) of the Ictidomys subgenus of ground squirrels was analyzed using chromosomal and electrophoretic techniques. Chromosomal variation was not observed in S. mexicanus, and only slight karyotypic variation was found in the other two species. Chromosomal evidence indicated hybridization between S. tridecemlineatus and S. mexicanus, placing these species within the classical definition of semispecies. Analysis of electrophoretic variation at 29 genetic loci indicated close genetic relationships between these species. Evolution in Ictidomys appears to be linked with Pleistocene events, and speciation appears to have occurred within the last 155,000 years.

Script from the WBAP-TV/NBC station in Fort Worth, Texas, relating a news story.

Script from the WBAP-TV/NBC station in Fort Worth, Texas, relating a news story about the Colonial National Tennis tournament, the Cowboys win over Cleveland, boxer Paul Rondon retains his championships, a potential blackout on Cowboys games in certain Texas areas, two talented 16 year olds win big, and the Texas State Karate Championships.

Script from the WBAP-TV/NBC station in Fort Worth, Texas, relating a news story about baseball game and several teams participating in it where Texas rangers defeated Atlanta braves by 7- 3.