I.V. Petrescu-Mag, B. Păsărin, G. Hoha, Valerica Gîlcă, Ruxandra Mălina Petrescu-Mag
Abstract
In this paper we report on a special case of crossing-over in Poecilia reticulata. It was known fact that Snakeskin body trait (Ssb) can be both X-linked, or Y-linked, and also that the percent of recombination between Y and X chromosomes is 0.36, while reciprocal recombination, from X to Y, is 0.00; in other words, the gene was not known to recombine from X to Y. The aim of the current work was to present an accidental observation about the occurrence of crossing-over events from X chromosome to Y chromosome in our guppy broodstock. The results based on crossbreeding and progeny testing showed that Ssb recombination by crossing-over or gene conversion is possible both from X to Y and Y to X. These events have numerous evolutionary implications as long the color traits and behavior are very close interrelated in many animal taxa and not only in the guppy fish.
Key words: crossing-over, Poecilia, Snakeskin body, progeny test
CARACTERUL SNAKESKIN BODY LA GUPPY: DE LA X LA Y
I.V. Petrescu-Mag, B. Păsărin, G. Hoha, Valerica Gîlcă, Ruxandra Mălina Petrescu-Mag
Rezumat
In prezenta lucrare relatam un caz particular de crossing-over, observat la specia Poecilia reticulata. Era cunoscut faptul ca tiparul Snakeskin body (Ssb) poate exista in forma X-linkata, sau Y-linkata, si ca procentul de recombinare genetica de pe cromosomul Y pe cromosomul X este de 0.36, in timp ce recombinarea reciproca, de pe X pe Y, este de 0.00. Scopul lucrarii a vizat prezentarea unor observatii conform carora crossing-overul genei Ssb are loc in ambele sensuri la guppy: atat de pe Y pe X cat si de pe X pe Y. Rezultatele obtinute, bazate pe incrucisari repetate si teste de progenitate, au o semnificatie deosebita, precum si implicatii in evolutia animalelor devreme ce caracterele de culoare si comportamentul sunt strans interrelationate in cadrul mai multor taxoni si nu doar in acest particular caz, al pestilor guppy.
Cuvinte cheie: crossing-over, Poecilia, Snakeskin body, test de progenitate
