Gene mapping by chromosome microdissection and microisolation in the chicken.

A chromosome microdissection and microisolation technique in combination with filter hybridization was developed for chromosomal localization of cloned chicken genes. The DNA was obtained from microdissected chromosome regions of metaphase spreads. Dissected DNA was amplified by polymerase chain reaction (PCR).

Association of dominant marker traits and metric traits in chickens.

This study was initiated to determine whether an allelic substitution of a dominant marker gene would identify a region close to a locus affecting expression in a metric trait. The rationale for the experiment was to utilize disequilibrium between a multiple recessive randombred Rhode Island Red (RRc) stock previously selected for quantitative trait performance and an unimproved dominant marker stock (MDM). The reporter genes in the MDM were: barring (B), silver (S), creeper (Cp), rose comb (R), double uropygial gland (U), crest (Cr), dominant white (I), frizzle (F), duplex comb (D), multiple spurs (M), polydactyly (Po), blue egg (O), pea comb (P), naked neck (Na), extended black (E), white skin (W+), muffs and beard (Mb), and feathered shanks (Fsh).

Mapping of the growth hormone gene by in situ hybridization to chicken chromosome 1.

In situ hybridization of a tritium-labeled chicken growth hormone cDNA to 62 chicken metaphase chromosome spreads was examined by analysis of silver grain distribution. A total of 554 chromosomally located grains were recorded. There was a highly significant P value for the association of silver grains to the long arm of chromosome 1.

Differential evolution in chromosomal composition during multiple cycles of subcutaneous and intravenous metastasis.

It has been proven that multiple cycles of metastasis can improve the metastatic potential and homing specificity of a tumor cell population. In the present study, verification of genetic alterations during changes in metastatic behavior was done by analyzing the chromosome composition of a methylcholanthrene induced murine fibrosarcoma, 3AM during multiple cycles of subcutaneous (SC) and intravenous (IV) metastasis. After 10 cycles of SC metastasis, a cell type, 7B, with a small t(19;19)(A;A) metacentric marker chromosome was enriched from 4% in the original population to 90% in FIOR.

Estimating meiotic disjunction frequencies in chicken translocation heterozygotes based on embryonic mortality.

Chickens heterozygous for a chromosomal translocation [MN t(1;4)] were intercrossed and the progeny were analyzed for their chromosome complement. A ratio of 1 homozygous translocation carrier to 4 heterozygous translocation carriers to 1 homozygous standard chromosome carrier was noted (n = 520), rather than the 1:2:1 ratio expected from Mendelian segregation. The excess of heterozygous carriers was apparently caused by union of complementary duplication/deficient gametes.