Myron Gordon

GENETICS OF FIN TRANSPLANTATION IN XIPHOPHORIN FISHES

Successful transplantations of fins between members of one highly inbred strain of platyfish, Xiphophrus maculatus, were shown to be feasible by Kallman and Gordon (1957). Since then, a second highly inbred strain of platyfish was developed in our laboratory that has provided the necessary material for an analysis of the genetic constitution of host and donor in determining whether a graft will be accepted or rejected. The present concept that the fate of a transplant depends upon histocompatibility genes is derived largely from experiments with inbred strains of mice and rats. It is desirable to determine if this genetic concept is applicable to other classes of vertebrates, especially the fishes. This paper is a report of some results that we have obtained thus far from our experiments with the transplantation of fins among members of two highly inbred strains of platyfish and their F1 hybrids.

Speciation in Fishes Distribution in Time and Space of Seven Dominant Multiple Alleles in Platypoecilus maculatus

Publisher Summary This chapter discusses the genetics of speciation in seven dominant multiple alleles in Platypoecilus maculates (P. maculates). The pattern names and the genetic symbols used for them are as follows: one-spot ( P o ), twin-spot ( P T ), crescent complete ( P Cc ), moon complete ( P Mc ), crescent ( Pc), moon (P M ), and comet ( P Co ). The patterns have been used as indices in the analysis of the genetic composition of natural fish populations of the Rios Jamapa, Papaloapan, Coatzacoalcos and Usumacinta of Mexico, and Guatemala. The genes are P o , P M , P Mc , P c , P Cc , P Co , P T , and P + the recessive. The entire series of seven patterns is found only in the platyfish populations of the Rio Papaloapan. The Rio Jamapa platyfish lack the genes P M and P Mc . The platyfish of the Rios Coatzacoalcos and the Usumacinta lack P c and P Co but these populations may be distinguished on the basis of the frequencies of their other genes. All seven patterns are formed by precise groupings of many small melanophores. Fortunately, the melanic patterns so produced arc unaffected by the preserving fluids. As a result, it has been possible to utilize and examine collections of P. maculatus in various museums, and classify the fish with respect to this and other series of heritable patterns. In this way a comparison of their gene frequency distributions at various time levels has been made of population from the same general area; some collections were taken 70 years apart.

Maintenance of polymorphism by potentially injurious genes in eight natural populations of the platyfish,xiphophorus maculatus

SummaryThe polymorphism of the platyfish,Xiphophorus maculatus, consists in part of a series of seven tail patterns produced by micromelanophores, which are controlled by an autosomal series of dominant multiple alleles. Also present are a series of five body patterns produced by macromelanophores which are controlled by an incompletely sex-linked series of dominant multiple alleles.

The Genetics of Fish Diseases

Abstract The clearest evidence for the hereditary determination of diseases in fishes comes from the genetic studies of melanomas. This neoplastic disease in platyfish-swordtail hybrids is initiated, intensified, or inhibited by genetic factors. The development of melanomas depends upon the interaction of a sex-linked, dominant gene obtained from the platyfish and a number of dominant modifying genes obtained from the swordtail. During the past 5 years, evidence has been discovered for the hereditary influence in the development of thyroid tumors in a species of Mexican swordtails. The disease closely resembles the well known thyroid tumors in trout, described about 50 years ago. Kidney tumors of thyroid-cell origin have been detected in several strains of platyfish. In other strains of the same species, living under similar conditions and diets, the kidney tumors have not developed. Several examples are presented of death of fish embryos from hereditary causes. Some skeletal abnormalities of fishes may b...

Effects of Alpha-estradiol Benzoate and Methyl Testosterone upon the Platyfish, Xiphophorus maculatus Skeleton.

Summary Alpha-estradiol benzoate induced the dissolution of one or two anterior hemal spines in a significant number of immature and maturing male platyfish but elicited no response in adult males. Methyl testosterone, administered to adult female platyfish, induced the fusion of 2 series of small, basal bony elements, the mesonosts and baseosts. The mesonosts ordinarily discrete, became fused to the ventral surfaces of the interhemal spines. The baseosts, normally bipartite, became unipartite.