Sheep gene mapping  by somatic cell hybridization

The identification of genes controlling several traits of interest in sheep has been accomplished by positional candidate cloning. In these studies, the trait is first mapped to a specific chromosomal region by linkage analysis, which requires families that are segregating for the trait and for polymorphic markers. Microsatellite markers are usually used for these analyses because of their extensive genetic variability. Once the location of a trait is determined by linkage to the markers, possible candidate genes controlling the trait can be inferred because of their proximity to linked markers. It is not necessary to map all possible genes in sheep for this strategy to be effective. Rather, a subset of genes that are mapped in humans and mice have also been mapped in sheep; these genes serve as "anchors" across the comparative maps of the different species. Further study of these positional candidates has revealed naturally occurring mutations that produce phenotypes that are unique to sheep. Thus the genetic analysis of sheep traits advances knowledge not only in this species but provides critical information for understanding biological pathways in mammalian species.

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“…Additional assignments for ϳ250 genes have been made using somatic cell hybrids (8,82) and in situ hybridization.…”

Section: The Sheep Genome Mapmentioning

confidence: 99%

Analysis of the sheep genome

Cockett

Shay

Smit

2001

Physiological Genomics

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“…In addition and as expected from linkage analysis (Levkziel et al 1991), CASB and CASK were also found to be syntenic (Table 2). No synteny was found between AMH and any other previously syntenic or unassigned group described by Saidi-Mehtar & Hors-Cayla (1981b) and Saidi-Mehtar et al 1981a, 1987 and Imam Ghali et al (1987) (see Table 1).…”

Section: Resultsmentioning

confidence: 64%

Sheep gene mapping: additional DNA markers included (CASB, CASK, LALBA, IGF‐1 and AMH).

1991

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Summary. DNA extracted from 25 hamster‐sheep hybrid cell lines was subjected, after Southern blotting, to hybridization with CASB, CASK, LALBA, IGF‐1 and AMH cDNA probes. CASB and CASK segregated together and IGF‐1 and LALBA were found syntenic with the LDHB‐PEPB‐TPI‐GAPD‐SHMT‐KRTB group. No other synteny was observed with any of the previously described groups using the same hybrid cell panel. Gene nomenclature: ACO 1: aconitase 1 (soluble); ADA: adenosine deaminase; AMH: antiMüllerian hormone; ARA 1: murine sarcoma 3611 viral (v‐raf) oncogene homologue 1; CASB: ß‐casein; CASK: K‐casein; ENO 1: enolase 1 (alpha); GAPD: glucose‐6‐phosphate dehydrogenase; GALA (or GLA): galactosidase (alpha); GAPD; glyceraldehyde‐3‐phosphate dehydrogenase; GPI: glucose phosphate isomerase; GSR: glutathione reductase; HBG: haemoglobin gamma; HPRT: hypoxanthine phosphoribosyl transferase; IDH 1: isocitrate dehydrogenase 1 (soluble); IGF‐1: insulin growth factor 1; ITPA: inosine triphosphatase; KRTA: keratin (acid); KRTB: keratin (basic); LALBA: aT‐lactalbumin; LDHA: lactate dehydrogenase A; LDHB: lactate dehydrogenase B; MDH 2: malate dehydrogenase NAD (soluble); ME 1: malic enzyme (soluble); MPI: mannose phosphate isomerase; NP: nucleoside phosphorylase; OLA: ovine leucocyte antigen: OTC: ornitine carbamoyltransferase; PAIS: phosphoribosyl amino imidazole synthetase; PEPA, PEPB, PEPC: peptidase A, B, C; PGD: phospho gluconate dehydrogenase; PGK: phosphoglycerate kinase; PGM 3: phospho glucomutase 3; PKM 2: pyruvate kinase (muscle); PLP: proteolipid protein; PRGS: phosphoribosyl glycinamide synthetase; RCP: red cone pigment; SHMT: serine hydroxymethyl transferase; SOD 1: superoxide dismutase 1 (soluble); SYN 1: synapsin 1; TPI1: triose phosphate isomerase 1.

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“…(34 ) Most of this work has been done with Chinese hamster ovary cells fused to sheep lymphocytes. (35)(36)(37) Chinese hamster ovary auxotrophic mutants have been particularly useful because these cells are deficient in an enzyme required for growth in a nutritionally deficient medium . After fusion, growth of the hybrids depends on retention of the com plem entary chromosom e that encodes the deficient gene product.…”

Section: Discussionmentioning

confidence: 99%

Generation of Sheep X (Sheep X Mouse) Heterohybridoma Cell Line Expressing the Beta-1 Integrin Membrane Molecule

He²,

West³

et al. 2000

Hybridoma

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Sheep are an important biological model in such diverse areas as immunology and reproductive biology. The limitation of sheep as an experimental model is the absence of reliable cell lines. To establish cell lines that express functional sheep membrane molecules, we produced a sheep x mouse heterohybridoma by fusion of sheep efferent lymph T cells with the murine myeloma cell line NS1. A cloned heterohybridoma fusion partner was selected by treatment with 8-azaguanine. The resulting cell line HL1/385 was selected for hypoxanthine/aminopterin/thymidine (HAT) sensitivity and growth efficiency. The HL1/385 cell line was used as a back-fusion partner into lectin-stimulated efferent T lymphocytes. The back-fusion approach produced more than 50 heterohybrid cell lines with high growth efficiency. The expression of physiological levels of the sheep beta-1 integrin cell surface molecule on the HT4/6 cell line was stable for months in culture. These results suggest that somatic heterohybrids may provide a reliable source of cell lines for sheep studies in vitro.

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Sheep gene mapping by somatic cell hybridization

Cited by 5 publications

References 7 publications

Analysis of the sheep genome

Analysis of the sheep genome

Sheep gene mapping: additional DNA markers included (CASB, CASK, LALBA, IGF‐1 and AMH).

Generation of Sheep X (Sheep X Mouse) Heterohybridoma Cell Line Expressing the Beta-1 Integrin Membrane Molecule

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