You might find this introduction of interest. The paper deals with inbreeding in isolated populations, but the introduction mentions many causes of spinal deformation before getting into the isolation as a cause.
Kerniske FF, Pena Castro J, De la Ossa-Guerra LE, Mayer BA, Abilhoa V, de Paiva Affonso I, Ferreira Artoni R. 2021. Spinal malformations in a naturally isolated Neotropical fish population. PeerJ 9:e12239
https://doi.org/10.7717/peerj.12239
Introduction
Fish species may develop different types of morphological deformities, such as dysplasia in the opercular bones, maxillary-mandibular apparatus, and mandibular bones; anomalies in fins and eyes (
Mise, Tencatt & Santos, 2017); bone and skin neoplasms; and spine deformations (
Flores-Lopes, Cetra & Malabarba, 2010). Dorsoventral (lordosis), lateral (scoliosis) or upward spinal curvature (kyphosis) malformations can cause anomalous body appearance (
Bengtsson, Bengtsson & Himberg, 1985) and be treated as monstrosities (
Golubtsov, Korostelev & Levin, 2021), but such anomalies are often not visible if only a few vertebrae are affected (
Gjerde, Pante & Baeverfjord, 2005;
Kvellestad et al., 2000;
Witten et al., 2006). Body and skeletal malformations have been reviewed in many publications and they are related to multiple physiological, environmental, xenobiotic, nutritional and genetic factors (
Slooff, 1982;
Wells & Cowan, 1982;
Toften, 1996;
Gjerde, Pante & Baeverfjord, 2005;
Jagiełło et al., 2017;
Madsen, Arnbjerg & Dalsgaard, 2001). Environmental factors have been linked to vertebral anomalies in
Salmo solar (
Fraser et al., 2015;
Ytteborg et al., 2010) and
Solea senegalensis (
Pimentel et al., 2014), whereas chemical substances were responsible for craniofacial deformities in
Sebastiscus marmoratus (
Zhang et al., 2012) and
Danio rerio (
Baker, Peterson & Heideman, 2013), and nutritional conditions covered a variety of deformities reported in finfish farming (
Berillis, 2015;
Eissa et al., 2021). Although genetic factors are usually considered marginal (reviewed in
Boglione et al., 2013), alteration in extracellular matrix gene transcription in Atlantic salmon (
Ytteborg et al., 2010), congenital ocular malformation and skeletal abnormalities in zebrafish (
Babcock et al., 2014), deformities in bream (
Afonso et al., 2000;
Afonso et al., 2009) and intrinsic correlation between lordosis and consanguinity (
Izquierdo, Socorro & Roo, 2010) are described in the literature. Skeletal deformities seem to be related to the early stages of development (
Longwell et al., 1992), however we still know little about the genetic factors responsible for such deformations (
Gjerde, Pante & Baeverfjord, 2005;
Jagiełło et al., 2017;
Kincaid, 1976).
Although morphological anomalies can occur both in farmed and natural fish populations, they are better investigated in aquaculture because deformities can downgrade fish production and result in economic losses (
Kause et al., 2005). Culture systems usually lead to a loss of genetic variability in stocks, causing inbreeding depression and associated deformities (
Aulstad & Kittelsen, 1971). Inbred populations are more susceptible to environmentally induced mortality, while also experiencing hampered growth rates and reproduction. Inbreeding can also impose difficulties for natural populations because it reduces intrapopulational genetic variability (
Kause et al., 2005) and increases frequency of deleterious alleles that are normally expressed in recessive homozygotes (
Keller, 2002).
You can use the link in the citation above to read the entire paper, But it mostly deals with a specific isolated population in Brazil.
