Attempt at conserving the genetic resources of Hu sheep by fibroblast line cryopreservation

Abstract

Hu sheep is one of the most distinctive local sheep breeds in China, while investigations concerning its cell biology and molecular genetics are still scarce. To preserve the valuable genetic resources of the Hu sheep, we established a Hu sheep fibroblast line from 35 sheeps' ear marginal tissues using explant culture and cryopreservation techniques, and its biological characteristics were identified, including cell morphology, growth curve, karyotype, isoenzyme polymorphism, and expression of exogenous fluorescent genes. The results showed that the viability of the fibroblasts before freezing was 96.54 ± 3.22% and 92.36 ± 2.77% after thawing, and there was no microbial contamination and crosscontamination; the growth curve of Hu sheep ear marginal fibroblasts displayed an obvious "S" shape; all somatic chromosomes were acrocentric autosomes, and only the two sex chromosomes (XY) were submetacentric; the normal number of chromosomes (2n = 54) was observed in 96.56 ± 2.89% of the cells; and the transfer efficiencies of four fluorescent proteins could achieve 37.4% with an optimized ratio of plasmid and lipofectamine. It could be concluded that this study has not only provided the biological characteristics of Hu sheep at cellular level, but also makes a valuable contribution to the preservation of the genetic resources of the Hu sheep.

Telomere-to-telomere sheep genome assembly reveals new variants associated with wool fineness trait

“…Potential assembly errors were manually checked and adjusted using Juicebox 75 (v2.18.0). Finally, all the scaffolds were anchored to 27 pseudochromosomes (26 autosomes and the X chromosome), which was consistent with the karyotype results in previous sheep studies 76,77 . We conducted an independent de novo T2T assembly of the Y chromosome, which is described in detail below.…”

“…The assembled graph was manually adjusted for gap filling, scaffolding, and correction, with assistance from the Y contigs using the trio-binning option of Hifiasm (v0.16.1) based on HiFi reads and 31-mers of the parents of HU3095. To validate the completeness and reliability of the above initial Y chromosome assembly, the Y chromosome (CP128831.1) from Ramb_v3.0 was included in the collinearity analysis using MUMmer 82 (v4.0.0), and the length of the Y chromosome assembled here was double checked based on the estimated karyotype length in previous studies 76,77 . Alignment of Bionano consensus maps against the Y chromosome was performed to examine possible assembly errors.…”

Enhanced Immune Responses with Serum Proteomic Analysis of Hu Sheep to Foot-and-Mouth Disease Vaccine Emulsified in a Vegetable Oil Adjuvant

“…Hu sheep is a local breed that originated in the Tai Lake Valley in Southeast China [ 25 , 26 ]. It has become an important economical animals in most areas of China as it has advantages of early sexual maturation, good reproductive performance with multiple offspring, genetic stability, and good adaptability to the environment [ 27 ].…”