Cross-species transferability of eastern white pine (Pinus strobus) nuclear microsatellite markers to five Mexican white pines.

We examined cross-species transferability and usefulness of six nuclear microsatellite markers developed in consubgeneric eastern white pine (Pinus strobus) with regard to ecologically and commercially important Mexican white pine species of conservation genetics concern: Pinus chiapensis (Mart.) Andresen, P. flexilis James, P. strobiformis Engelm., P. ayacahuite Ehrenb. Ex Schltdl, and P. ayacahuite var. veitchii (Roezl) G.R. Shaw. Four to six microsatellite loci were found to be polymorphic in different species, with moderate to high informativeness in a relatively small number of samples (PIC/HE=0.25-0.93). This successful transfer sidesteps the time- and resource-consuming development of species-specific microsatellite markers, and will facilitate population and conservation genetic studies and genetic resource management of the less studied Mexican white pines.

beta(A) globin gene haplotypes in Mexican Huichols: Genetic relatedness to other populations.

The haplotypes of 97 beta(A) independent chromosomes from a Mexican Huichol Native American group were analyzed. The analysis also included 87 beta(A) chromosomes from a Mexican Mestizo population previously studied. Among Huichols, eight different 5' beta haplotypes (5Hps) were observed, with types 1(+ - - - -), 13(+ + + - +) and 2(- + + - +) at frequencies of 0.794, 0.093, and 0.041, respectively. In Mestizos, 17 5Hps were found, types 1, 3(- + - + +), 2, 5(- + - - +) and 9(- - - - -) being the most common at frequencies of 0.391, 0.172, 0.092, 0.069, and 0.046, respectively. 3' haplotype (3Hps) frequency distributions were 0.443(+ +), 0.083(+ -), and 0.474(- +) in Huichols and 0.563(+ +), 0.149(+ -), and 0.287(- +) in Mestizos. Pairwise comparison for both haplotype distributions between the two populations showed significant differences. Pairwise distributions of 3Hps for Huichols were compared with nine worldwide populations, three African, two Asian, two Melanesian, one Caucasian, and one United States Native American. The distributions of the Huichol were different (P < 0.05) from all populations except the Native American. Nei's genetic distances showed the Huichols to be closer to the Native Americans, followed by Melanesians from Vanuatu and Asians; Africans were the farthest. The 5Hp distributions in Mexicans were also compared with 23 worldwide populations (including African, Native American, Asian, Caucasian, and Pacific Islanders). Huichol distributions were different (P < 0.05) from all other populations except Koreans. The Mestizo distribution was also different from the others, except three Caucasian groups. Nei's genetic distance between the same populations disclosed that the Huichols are in relatively close proximity to five out of six Asian populations considered. The same analysis with grouped worldwide populations showed Native Americans as population closest to the Huichols, followed by Pacific Islanders and Asians. Present observations are consistent with an important Asian contribution to the Huichol genome in this chromosomal region. Am. J. Hum. Biol. 12:201-206, 2000. Copyright 2000 Wiley-Liss, Inc.

Hb D-Los Angeles associated with Hb S or beta-thalassemia in four Mexican Mestizo families.

Twenty-five individuals were studied from four unrelated Mexican Mestizo families with Hb D-Los Angeles. We observed five compound heterozygotes: four for Hb S and Hb D, and one for Hb D and beta-thalassemia (beta(0) 39 nonsense mutation); 16 heterozygotes: four for Hb S, seven for Hb D, and five for beta-thalassemia, while the remaining four were normal. The four Hb S/Hb D patients had severe hemolytic anemia, while in the Hb D/beta-thalassemia patient, the anemia was similar to that of a beta-thalassemia heterozygote; therefore, Hb D is clinically harmful when it is associated with Hb S. The beta(S) chromosomes were associated with the Benin haplotype in two families and Bantu in one family, while the beta(D) and beta(0) 39 mutations were associated with haplotype 1 [+ - - - - + +]. The Bantu and Benin haplotypes have been found with high frequency in Hb S individuals from the East Coast and Northwestern Mexico. The beta(D) chromosomes from Italy were also shown to be associated with haplotype 1, the most frequently observed haplotype in the world; there are no haplotype studies on beta(D) chromosomes from India or China where Hb D-Los Angeles is most common. Thus, the true origin of this mutation observed in these Mestizo families remains to be elucidated.

Alpha-thalassemia in a selected population of Mexico.

OBJECTIVE: To identify by molecular biology the alleles of alpha-Thal in selected hospital populations. METHODS: Eighteen propositi with hematological and biochemical data suggestive of alpha-thalassemia, selected from 356 patients of four hospitals in two cities with probable hemoglobinopathy were investigated for six common alpha-Thal alleles. Molecular studies were done by PCR and digestion with specific restriction enzymes. RESULTS: The alpha 3.7 allele was identified in two cases and the family study revealed the same allele in the mother; HbS heterozigocity was also detected in one of them. An analysis with Apa I demonstrated a class I deletion in both patients. The present study showed 2/356 (0.6%) of alpha 3.71 carriers which is a low frequency as compared with other countries. As no other common alpha-thalassemia alleles were found, we suspect that alpha-Thal in Mexico is as heterogeneous at a molecular level as beta-Thal.

Hb Lepore Washington-Boston in two Mexican mestizo families.

Two Mexican mestizo families with Hb Lepore Washington-Boston are described. One family is from Cordova, in the State of Veracruz, in the East coast of Mexico: the proband is a 44-year old asymptomatic male with italian ancestors; the other family is from the city of Durango, State of Durango, in the northwestern part of the country: the propositus is a 32-year old pregnant female with French ancestors. In both cases the Hb Lepore was identified by alkaline electrophoresis and characterized by high performance liquid chromatography and PCR with specific probes flanking the deletion frame. The beta-haplotype in both families was +(-)-(-)-(++), the commonest beta-haplotype reported with this mutation. This paper describes the first cases of this entity in Mexico.

Beta-thalassemia and beta[A] globin gene haplotypes in Mexican mestizos.

B-globin haplotypes of 20 beta-thalassemia (beta-thal) and 87 beta(A) Mexican mestizo chromosomes were analyzed to ascertain the origin of the beta-thal alleles and the frequencies and distribution of the beta(A) haplotypes among northwestern Mexican mestizos. Sixteen beta-thal chromosomes carried six Mediterranean alleles [five codon 39 C-->T; two IVS1:1 G-->A; two IVS1:5 G-->A; three IVS1:110 G(A; one codon 11 (-T) and three (deltabeta)zero-thal]; the remaining four were linked to three rare alleles (two -28 A-->C and one each: -87 C-->T and initiation codon ATG-->GTG). Among the 87 beta(A) chromosomes, 17 different 5' haplotypes with frequencies for 1, 3, 2 and 5 of 39.0%, 17. 2%, 9.2% and 6.9%, respectively, were observed. The beta-haplotype analysis showed that 13 out of 16 Mediterranean chromosomes could easily be explained by gene migration; however, one codon 39 associated with haplotype 4 (----+ +-), one IVS1:1 with haplotype 1(+----++) and one IVS1:5 G-->A, may represent separate mutational events. Analysis of the rare alleles showed that the -28 A-->C mutation was associated with the commonest beta(A) haplotype in Mexican mestizos, Mediterraneans and the total world population; therefore an independent origin cannot be ruled out. The -87 C-->T and initiation codon ATG-->GTG were found with beta-haplotypes different from the reported ones, suggesting an indigenous origin.

Haplotype analysis of the Mexican frameshift Cd 11 (-T) and -28 A->C beta-thalassemia alleles.

The origins of the -28 A->C and frameshift Cd 11 - T(Fs CD 11-T)alleles were investigated by beta-globin cluster haplotype analysis. These alleles were found in a Mexican mestizo family with beta-thalassemia (beta-thal). The -28 A->C mutation was described previously in Kurdish Jews linked to the most common haplotype in the world(+----++),the same haplotype observed in this Mexican family. Therefore, it is not possible to assess a new origin of the -28 A->C mutation in our population. The Fs Cd 11 -T allele, not reported to date in any other populations, was linked to the -++--+-haplotype (sixth in frequency in the world). This haplotype has not been reported in association with any beta-thal mutant, suggesting a Mexican origin for the Cd 11 -T mutation.

[Thalassemic alleles in Mexican mestizos]. / Alelos talasémicos en mestizos mexicanos.

We present an analysis of the thalassemic alleles observed in Mexican mestizos. In 18 unrelated patients with mild to severe hemolytic anemia we saw 16 with beta-thal and two with alpha-thal and identified 25 chromosomes with 14 different alleles (10 for beta-thal), predominating the Mediterranean type (seven beta-thal and two alpha-thal). The most common mutation was the nonsense Cd 39 observed in seven chromosomes (28%); the other mutants were three Asian alleles, one beta-thal Indian (IVS-1 nt 5 G-->C), two Southeast Asian alpha-thal (-SEA and the -FIL), one Kurdish Jew (-28 A-->C) and one Mexican (Cd 11 -T). These findings suggest a marked molecular heterogeneity in the thalassemia genes in Mexico.

[Fetal hemoglobin and the gamma G/gamma A chain ratio in children with acute lymphoblastic leukemia L1 and L2]. / Hemoglobina fetal y relación de cadenas gamma G/gamma A en niños con leucemia aguda linfoblástica L1 y L2.

PURPOSE: To search in children with acute lymphoblastic leukaemia (ALL) for specific pattern of expression of foetal haemoglobin (HbF) and its G gamma/A gamma chain ratio. MATERIAL AND METHODS: 60 children with ALL were examined: 29 with ALL-L1, and 31 with ALL-L2, and 25 healthy children as control group, which were subdivided in three groups: A) 0-5, B) 6-10 and C) 11-18 years. We performed HbF and HbA2 quantification and Hb electrophoresis. G gamma and A gamma globin chain percentages were obtained with a new method based on the precipitation of the HbF eluate by Singer's method with sulphosalycilic acid, the globin chains were separated in polyacrylamide with Triton X-100 and quantified by densitometry. RESULTS: HbF showed similar levels in both ALL groups by the Betke and Singer's methods; (ALL-L1: 2.2 +/- 1.5%, ALL-L2: 2.0 +/- 1.2%; and ALL-L1: 2.0 +/- 1.2%, ALL-L2: 2.1 +/- 1.5% respectively), but there were statistically significant differences (p < 0.001) when compared with the control group (0.9 +/- 0.4%, and 1.0 +/- 0.6% for Betke and Singer's method). The G gamma/A gamma ratio showed to be different between the ALL-L1 and ALL-L2 (p < 0.001), with higher levels of G gamma in ALL-L1 (51.0%), the ALL-L2 and the control group showed similar G gamma values (37.5% and 42.1% respectively). CONCLUSION: The factors involved in the increase of HbF are similar for both ALL-L1 and ALL-L2. However there seems to be different factors affecting the expression of G gamma or A gamma.