Y chromosome of ethnic groups in Macedonia

[hyllus]

Introduction

Spoiler: 

The analysis of single nucleotide polymorphisms (SNPs), located within the non recombining region of the Y chromosome (NRY), has been widely accepted in molecular anthropology as a unique tool for evolutionary studies. The low mutation rate and specific distribution of Y-haplogroups in populations, allow for the reconstruction of origin, evolution, and history of groups of humans by tracing male patterns of migration backwards from modern human populations [1]. Y-single nucleotide polymorphisms also constitute forensic tools because they can significantly contribute to forensic analysis by providing information on the ethnic origin of a male DNA sample [2]. Combined with conventional markers, they could be a powerful tool in mass disasters where people from various geographical areas are involved. Recently, Y-SNP typing has been applied in the study of possible association of Y-haplogroups with male-specific (spermatogenic failure, testes and prostate cancer) and prevalently male-associated (hypertension, autism) diseases.

The Y Chromosome Consortium has published a single most parsimonious phylogeny of 153 binary haplogroups based on 243 binary markers and developed a simple set of rules to label unambiguously the different clades nested within this tree [4]. An extensively revised Y chromosome tree containing 311 distinct haplogroups, incorporating approximately 600 binary markers has also been published [5] and a web-based document with a regularly updated version of the Y chromosome tree has also become available .

In recent years, many different SNP typing techniques have been developed on the basis of various methods of allelic discrimination and detection platforms . Most of these are based on allele specific hybridization, primer extension, oligonucleotide ligation or invasive cleavage. Detection methods for the products of each type of reaction, include fluorescence, luminescence and mass measurement. We selected the SNaPshot minisequencing approach which consists of single base extension of an unlabeled primer that anneals one base upstream to the relevant SNP. A multiplex minisequencing assay has already been validated for genotyping of the Y chromosome. These studies have shown this SNP typing methodology to be robust, reliable and extremely sensitive. We have used a rapid, simple and inexpensive strategy for Y chromosome SNP typing of the multiethnic Macedonian population.

Materials and Methods

Materials. We have studied 343 DNA male DNA samples from the DNA bank at our institution, of which 211 were Macedonians, 111 Albanians and 21 Roma, Serbs or Turks. The study was approved by the Ethics Committee of the Macedonian Academy of Sciences and Arts, Skopje, Republic of Macedonia (R. Macedonia).

Methods. The set of 28 Y-SNP markers was grouped hierarchically into five multiplex polymerase chain reaction (mPCR)/primer extension reactions, so as to determine the most frequent haplogroups using one or two multiplexes (Figure 1). Most of the PCR and minisequencing primers have already been described [8], the remainder were designed by us.

Results

Multiplex 1 consists of eight SNPs and allows detection of the more frequent major clades in Europe. It also includes the 12f2 deletion, which determines haplogroup J and was typed by presence/absence in the PCR amplification (Figure 2). Multiplex 1 determines haplogroups R1b1-P25, R1a1-SRY1532 and I2a-P37b. We performed multiplex 1 in all samples, and depending on the results, multiplex 2, 3, 4 or 5 was performed in order to define the haplogroup more precisely.

Multiplex 2 comprises four SNPs, multiplex 3 and 4 comprise six SNPs each, while multiplex 5 is a combination of five SNPs. Multiplex 2 subdivides haplogroup I, multiplex 3 haplogroup E, multiplex 4 haplogroup J, while haplogroup 5 determines haplogroups G-M201, H-M69, L-M22, N1c-Tat and T-M70.

Among the DNA samples we studied, we detected 20 different Y haplogroups, of which five haplogroups (E1b1b1a-M78, I2a-P37b, J2b2-M241, R1a1-SRY1532 and R1b1-P25) comprised 72.6% of the studied Y chromosomes (Table 3). The distribution of the Y haplogroups in Macedonians, Albanians and males of other ethnic origin (Roma, Serbs and Turks) is given in Table 3. The most common Y haplogroup in Macedonians was I2a-P37b (27.5%), which was followed by E1b1b1a-M78 (15.6%), R1a1-SRY1532 (14.2%) and R1b1-P25 (11.4%). In the Albanians, E1b1b1a-M78 was found in 28.8%, R1b1-P25 in 18.0%, J2b2-M241 in 13.5% and R1a1-SRY1532 in 12.6%. In the small group of Roma, Serbs or Turks, R1b1-P25 was found in 23.8% and E1b1b1a-M78 and H-M69 in 14,3% each. All three males with haplogroup H-M69 were of Roma ethnic origin.

Discussion

The R. Macedonia has a multiethnic population consisting of Macedonians (64.2%), Albanians (25.2%) and Roma, Serbs, Turks, Aromuns and others (10.6%) (2002 census). The most common Y haplogroups in this population are E1b1b1a-M78, I2a-P37b, J2b2-M241, R1a1-SRY1532 and R1b1-P25. Y haplogroup composition of the population conforms with previous findings in the Southeast European (SEE) population [10].

The Y haplogroup E1b1b1a-M78 was the most frequent haplogroup in Albanians and the Roma, Serb or Turk group, but was second in frequency in Macedonians. It is the most common haplogroup E lineage in Europe with a frequency peak centered in the Balkans [11,12]. It is also found in the Middle East and in eastern and northern Africa. Its frequency in Kosovar Albanians (46%) and Macedonian Roma (30%) is most likely a result of genetic drift [10].


The most frequent haplogroup in Macedonian males is I2a-P37b (27.5%), which has maximum frequency in Herzegovinians (64%) and Bosnians (52%) and substantial frequencies in all SEE populations except for two reproductively isolated and non slavic speaking populations, Kosovar Albanians and Macedonian Romani [10]. In the Albanians in Macedonia, I2a-P37b had a very low frequency (1.8%) (Table 3), similar to Albanians from Kosovo (2.7%) and different from Albanians in Albania (17%) [10].


The R1b1-P25 haplogroup showed an overall frequency of 14.3%, being 18.0% in Albanian and 11.4% in Macedonian subjects. This lineage shows a frequency peak (40-80%) in western Europe and decreases in eastern (with the exception of 43% in the Ossetians) and southern Europe [13,14]. However, it shows two intermediate local peaks in mainland Croatians and Serbians, and among Kosovar Albanians, Albanians and Greeks [10].


The R1a1-SRY1532 haplogroup showed similar frequencies in Macedonians and Albanians and was less frequent in the Roma, Serb or Turk groups. The frequency in Macedonia agrees with that of 16% determined in SEE [10]. Its distribution increases from west to east with peaks in Finno-Ugric and Slavic populations. R1a1-SRY1532 frequency decreases slowly to the south of Europe.


Haplogroup J is defined by a 12f2 polymorphism and has two major subclades, J1-M267 and J2-M172, of which the latter is more prevalent in Europe [15]. The J2b-M102 lineages are more frequent in SEE comprising 5% of all chromosomes, with a peak in Kosovar Albanians [10]. The J2a4b-M67 cluster is predominant in Greeks and Italians [16]. The J2b2-M241 was the fifth most frequent Y haplogroup in the populations of R. Macedonia due to its high prevalence in Albanians (13.5%).


The most significant difference (p <0.0001) was found in the case of Hgr I2a-P37b, which was prevalent (27.5%) in Macedonians and infrequent in Albanians (1.8%). Although present at a relatively low frequency in both groups, I1-M253 was significantly more frequent in Albanians (6.3 vs. 1.9% in Macedonians, p = 0.0383). The E1b1b1a-M78 haplogroup was statistically more frequent in Albanians (28.8 vs. 15.6% in Macedonians, p = 0.0050). The same applies to J2b2-M241 (13.5 vs. 5.2%), being more common in Albanians (p = 0.0093). The R1a1 and R1b1 haplogroups were present with similar frequencies in both populations.

In conclusion, we have developed a simple, robust and efficient Y-SNP typing assay that can find application in evolutionary and forensic studies in the major ethnic groups of R. Macedonia. The hierarchical strategy using the SNaPshot multiplex kit (Applied Biosystems) made Y chromosome SNP typing rapid and inexpensive.

Source

What is interesting is the absence of I2a among Macedonian Albanians just as the Kosovo Albanians.

Macedonian Albanians have slightly lower R1a percentage(12.6%) than Macedonians but they have 6.3% I1-M253 a similar percentage to Kosovo Albanians.

[hyllus]

A six-year long DNA study of Balkan peoples conducted by the Skopje Forensics Medicine Institute has showed a remarkable resemblance among the three groups.

“The analysis of the data has showed that residents of Macedonia share the most DNA with Bulgarians; Serbs and Croats with Bosniaks; while Kosovo Albanians have the fewest similarities with the others,” says the Institute’s Dr Zlatko Jakovski.

Macedonian scientists received samples and data from most of the Balkan countries, except from Greece, which refused to take part in the project. All the other countries sent DNA analyses of persons who had died in their territory to the institute in Skopje.

“By using sophisticated computer technology we have compared the data from Macedonia, Serbia, Bosnia, Bulgaria, Croatia and Kosovo,” Jakovski explained.

The research has been published in leading world forensics magazines and the results will be used in criminal investigations in cases when victims are from the Balkans.

"For example [it could be used] in the identification of the victims of the plane crash that killed Macedonian President Boris Trajkovski [in 2004]. It will also be used in proving the paternity of Macedonian children when it is suspected that their parents are from Serbia, Croatia and Kosovo," said Jakovski.

Dr. Jakovski pointed out that the research represented a very useful scientific project and had nothing to do with daily politics in a region where ethnicity has often been a reason for conflict.

Source

[gr2001]

Very logical.

[Polako]

The R1b1-P25 haplogroup showed an overall frequency of 14.3%, being 18.0% in Albanian and 11.4% in Macedonian subjects. This lineage shows a frequency peak (40-80%) in western Europe and decreases in eastern (with the exception of 43% in the Ossetians) and southern Europe [13,14].

Does that sound right?

[hyllus]

Does that sound right?

I realized that too.

[safinator]

The most interesting thing about the study is the fact that Albanians and Macedonians share almost the same percentage of R1a.

[joseph capelli]

The most interesting thing about the study is the fact that Albanians and Macedonians share almost the same percentage of R1a.

Does it mean that I2a1b is the most south slavic haplotype?

[uncut]

Very interesting study.
Thanks.

In the Albanians in Macedonia, I2a-P37b had a very low frequency (1.8%) (Table 3), similar to Albanians from Kosovo (2.7%) and different from Albanians in Albania (17%) [10].

Makes sense, I think.

[safinator]

Does it mean that I2a1b is the most south slavic haplotype?

Very likely although R1a is still fairly common among Yugoslavs.

[Alaron]

Does it mean that I2a1b is the most south slavic haplotype?

I2a1b is definitely a South Slavic marker. Genetically Balkans seems to be a melting point . Albanians have some amount of Slavic and Greek/Anatolian admixture.

The most interesting thing about the study is the fact that Albanians and Macedonians share almost the same percentage of R1a.

We don't know what kind of R1a subclades. They can be of Slavic extraction. It will not surprise me.