Allele frequency distributions of YNZ22 and IG-J_H in the Lithuanian population.

Allele and genotype frequencies for the YNZ22 and Ig-J_H loci have been determined in a Lithuanian population samples using the polymerase chain reaction (PCR) amplification. In 215 unrelated individuals of YNZ22 locus, 12 different alleles and 49 different genotypes were observed. For Ig-J_H locus in 200 individuals samples a total of 24 different genotypes and 11 alleles were observed.

Introduction

In human genome contain a large number of DNA segments of tandemly repeated sequences as VNTR (Variable number of tandem repeats) loci.

The technique of amplification "in vitro" using the polymerase chain reaction (PCR) has been applied successfully to amplify several VNTR. The presence of large number of alleles at VNTR loci also makes them useful in the context of paternity testing, forensic medicine and population genetics.

In order to obtain population data in the Lithuania, allele frequencies and genotype distribution of two polymorphic loci (YNZ22 and Ig-J_H). The Ig- J_H VNTR locus, situated on chromosome 14, the polymorphism detected using PCR consists of 13 alleles, ranging in length from 420 bp to 1020 bp with a 50 bp core sequence. The VNTR locus detected previously by probe YNZ22 on 17p13.3 chromosome is considered a useful marker. The polymorphism detected using PCR consists of 14 alleles, ranging in length from 170 bp to 1080 bp with a 70 bp core sequence.

Material and methods

DNA samples were collected from blood samples in the Lithuania corresponding to parents of families involved in paternity analysis. DNA was extracted from fresh blood leukocytes using Chelex extraction method.

DNA samples from 215 individuals were used for analysing the YNZ22 polymorphism. For the Ig- J_H study 200 individuals DNA samples were typed.

The amplification was carried out with the following primer sequences and conditions:

1. YNZ22

5' AAA CTG CAG AGA GAA AGG TCG AAG AGT GAA GTG

5' AAA GGA TCC CCC ACA TCC GCT CCC CAA GTT

2. Ig-JH

5' GGG CCC TGT CTC AGC TGG GGA

5' TGG CCT GGC TGC CCT GAG CAG

Temp.: 94^oC/63 ^oC/72 ^oC

Time: 30s/1min/2min

Cycles: 30.

PCR reactions were carried out in a 25 or 50 m l volume containing 5-50 ng genomic DNA template.Detection of the different alleles from PCR amplified products were carried out by agarose gel electrophoresis. The gel mixture contained 2,0% agarose in a 1xTAE buffer with ethidium bromide.

Results and discussion

After studying 215 unrelated individuals of YNZ22 locus, 12 different alleles and 49 different genotypes were distinguishable in that locus ranging in size 170-940 b.p. The highest frequencies observed three alleles 240, 310 and 380?b.p. (0.1372, 0.1884 and 0.3256) - Table 1.

For Ig-J_H locus a total of 24 different genotypes and 11 alleles were observed in 200 individuals. Two alleles - 570 and 670 b.p., were found to be relatively common for the Lithuanian sample, with frequencies of 0,4825 and 0,2600, respectively (Table 2). Distribution of YNZ22 genotypes in a samples of 215 Lithuanians are presented in Table 3, of Ig-J_H genotypes in a samples of 200 Lithuanians - in Table 4.

From a forensic point of view the YNZ22 and Ig-J_H polymorphisms have been examined in paternity cases. Based on the allele frequencies, heterozygosity index, power of discrimination, chance exclusion and Essen-Moller value were calculated. The combined values show a high efficiency of forensic studies.

Table 1. YNZ22 allele frequencies from 215 Lithuanian individuals

Allele	Allele size	n	F
1	170	22	0,0512
2	240	59	0,1372
3	310	81	0,1884
4	380	140	0,3256
5	450	17	0,0395
6	520	12	0,0279
7	590	9	0,0209
8	660	10	0,0233
9	730	24	0,0558
10	800	34	0,0791
11	870	8	0,0186
12	940	14	0,0325
13	1010??	-	-
14	1080??	-	-
14(12)	?	430	1,0000

Table 2. Ig-J_H allele frequencies from 200 Lithuanian individuals

Allele	Allele size	n	F
07	420	2	0,0050
08	470	47	0,1175
09	520	10	0,0250
10	570	193	0,4825
11	620	1	0,0025
12	670	104	0,2600
13	720	3	0,0075
14	770	-	-
15	820	1	0,0025
16	870	11	0,0275
17	920	25	0,0625
18	970	3	0,0075
19	1020??	-	-
13 (11)	?	400	1,0000

Table 3. Distribution of YNZ22 genotypes in a sample of 215 Lithuanians

Genotype	n	F	Genotype	n	F
170-170	1	0,005	310-940	2	0,009
170-240	2	0,009	380-380	29	0,135
170-310	4	0,019	380-450	3	0,014
170-380	7	0,033	380-520	4	0,019
170-450	2	0,009	380-590	4	0,019
170-520	1	0,005	380-660	3	0,014
170-590	1	0,005	380-730	4	0,019
170-800	2	0,009	380-800	9	0,042
170-940	1	0,005	380-870	3	0,014
240-240	10	0,047	380-940	2	0,009
240-310	9	0,042	450-450	2	0,009
240-380	18	0,084	450-730	2	0,009
240-450	1	0,005	450-870	1	0,005
240-590	3	0,014	450-940	1	0,005
240-660	3	0,014	520-590	1	0,005
240-730	1	0,005	520-660	1	0,005
240-800	2	0,009	520-730	1	0,005
310-310	11	0,051	520-940	1	0,008
310-380	25	0,116	730-730	2	0,009
310-450	3	0,014	730-800	6	0,028
310-520	3	0,014	730-870	1	0,005
310-660	3	0,014	730-940	4	0,019
310-730	1	0,005	800-800	3	0,014
310-800	6	0,028	800-940	3	0,014
310-870	3	0,014	?	?	?

49 genotypes

Homozygosity (n = 58) = 0,270

Heterozygosity (n = 157) = 0,730

Table 4. Distribution of Ig-J_H genotypes in a sample of 200 Lithuanians

Genotype	n	F
420-620	1	0,005
470-920	1	0,005
470-470	3	0,015
470-570	21?	0,105
470-670	16??	0,080
470-720	1	0,005
470-870	1	0,005
470-920	2	0,010
520-570	5	0,025
520-670	5	0,025
570-570	49??	0,245
570-670	51??	0,255
570-720	1	0,005
570-870	6	0,030
570-920	9	0,045
570-970	2	0,010
670-670	11??	0,055
670-820	1	0,005
670-870	2	0,010
670-920	6	0,030
670-970	1	0,005
720-920	1	0,005
870-920	2	0,010
920-920	2	0,010

24 genotypes

Homozygosity (n = 65) = 0,325

Heterozygosity (n = 135) = 0,675

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