Slick hair

Phene ID

2729

Name

Slick hair

Phene Name

N/A

OMIA ID

1372

Species ID

9913

Characterised

Yes

Characterised Year

2014

This single-locus autosomal dominant trait confers increased thermotolerance within the breeds in which it originated (Senepol and Carora; Olsen et al., 2003) and also within Hosteins, into which it was introgressed (Dikmen et al., 2008; 2014).
In the USA, FDA determined in March 2022 that beef cattle with a genome edit to the PRLR gene and their offspring do not raise any safety concerns. "Based on the safety of consumption of meat from conventional breeds with the same mutation, the FDA finds no reason to regulate these CRISPR cattle. ... These cattle are the third genetically altered animals to be approved by the FDA, after AquaBounty’s AquAdvantage salmon and Revivicor’s GalSafe pigs." (PMID:35418643) (GMO)

Olson et al. (2003) reported "a major gene (designated as the slick hair gene), dominant in mode of inheritance, that is responsible for producing a very short, sleek hair coat . . . in Senepol cattle and criollo (Spanish origin) breeds in Central and South America . . .[and] in a Venezuelan composite breed, the Carora, formed from the Brown Swiss and a Venezuelan criollo breed".
Sosa et al. (2021) "evaluated whether the inheritance of the SLICK1 allele ...is inherited in a fashion consistent with Hardy–Weinberg equilibrium. It was hypothesized that any deleterious effect of inheriting the allele on embryonic or fetal function would result in reduced frequency of the allele in offspring. A total of 525 Holstein and Senepol cattle produced from matings involving one or both parents with the SLICK1 allele were genotyped. The observed frequency of the SLICK1 allele (0.247) was not significantly different than the expected frequency of 0.269. These results support the idea that inheritance of the SLICK1 allele does not act in the embryo or fetus to modify its competence to complete development to term."

By sequencing the most likely positional functional candidate gene within the BTA20 region to which this trait had been mapped (see Mapping section), Littlejohn et al. (2014) identified a causal mutation as "a single homozygous frameshift mutation . . . consisting of a single base deletion in exon 10 that introduces a frameshift and a premature stop codon (p.(Ala461fs) and loss of 120 C-terminal amino acids from the long isoform of the receptor (ss1067289408; chr20:39136558GC>G".
Porto-Neto et al. (2018) identified two other likely causal variants in the same PRLR gene, namely the stop-gained (nonsense) variants p.Ser465∗ (in the Limonero breed) and p.Arg497∗ (in the Carora and Limonero breeds). These two variants "explained almost 90% of investigated cases of animals that had slick coats, but which also did not carry the Senepol slick allele"; which indicates that there are more likely causal variants for slick hair yet to be discovered. Flórez.
Murillo et al. (2021) discovered three new variants, namely SLICK4, SLICK5 and SLICK6 (details in variant table below).
Zayas et al. (2024) "evaluated the effectiveness of genetic introgression of the SLICK1 allele derived from Senepol cattle into the Holstein breed to enhance thermotolerance. ... The study demonstrates the successful use of genetic interventions to improve livestock resilience against environmental challenges without significantly disrupting the recipient breed's genetic structure."
Gebeyehu et al. (2025) identified the SLICK2 variant in West African taurine and Zebu crossbred cattle.