?Early morphological background adaptation in the medaka Oryzias latipes depends on growth hormone receptor type 1

DELGADÍN TH; CASTAÑEDA, D; SACKS, CLARA; BRECCIA, ANDRÉS; FERNANDINO, JI; VISSIO, PG

Congreso; LATIN AMERICAN SOCIETY FOR DEVELOPMENTAL BIOLOGY (LASDB) MEETING 2019; 2019

Morphological background adaptation is both an endocrine and a nervousresponse to the surrounding environment that many fi shes are able to displayowing to changes in the amount and shape of specialized cells calledchromatophores located in the skin. However, it is not known if such a processtakes place at early developmental stages. Somatolactin (SL) is a pituitaryhormone present in fish that has been related to skin pigmentation. Althoughgrowth hormone receptor type 1 (GHR1) has been suggested to be the SLreceptor in some fish species and it has been demonstrated an associationbetween SL and GHR1 with adaptation to dar k backgrounds, there is evidenceagainst to GHR1 as SL receptor. The aim of this work was to evaluate at whatmoment on ontogeny morphological adaptation to background first occur and if itdepends upon GHR1, the putative SLR. We analyzed the amount ofchr omatophores in medakas reared from egg fertilization to white or blackbackgrounds at 9, 21, 16, 21 and 25 days post hatching (dph). We repeated thisprotocol at 16 and 21 dph for CRIPSR/Cas9 GHR1 mutant medaka and Cas9controls. By 16 dph, black adapted m edaka presented more melanophores thanwhite adapted ones (p=0.0001). This adaptation was severely reduced in GHR1deficient medaka (p