Refining the genetic portrait of Portuguese Roma through X-chromosomal markers

Vania Pereira; Leonor Gusmão; Cristina Valente; Rui Pereira; João Carneiro; Iva Gomes; Niels Morling; António Amorim; Maria João Prata

doi:10.1002/ajpa.22061

Refining the genetic portrait of Portuguese Roma through X-chromosomal markers

Vania Pereira, Leonor Gusmão, Cristina Valente, Rui Pereira, João Carneiro, Iva Gomes, Niels Morling, António Amorim, Maria João Prata

4 Citations (Scopus)

Abstract

Due to differences in transmission between X-chromosomal and autosomal DNA, the comparison of data derived from both markers allows deeper insight into the forces that shape the patterns of genetic diversity in populations. In this study, we applied this comparative approach to a sample of Portuguese Roma (Gypsies) by analyzing 43 X-chromosomal markers and 53 autosomal markers. Portuguese individuals of non-Gypsy ancestry were also studied. Compared with the host population, reduced levels of diversity on the X chromosome and autosomes were detected in Gypsies; this result was in line with known patterns of genetic diversity typical of Roma groups. As a consequence of the complex demographic past of the Roma, during which admixture and genetic drift played major roles, the amount of linkage disequilibrium (LD) on the X chromosome in Gypsies was considerably higher than that observed in non-Gypsies. When the pattern of differentiation on the X chromosome was compared with that of autosomes, there was evidence for asymmetries in female and male effective population sizes during the admixture between Roma and non-Roma. This result supplements previous data provided by mtDNA and the Y chromosome, underlining the importance of using combined information from the X chromosome and autosomes to dissect patterns of genetic diversity. Following the out-of-India dispersion, the Roma acquired a complex genetic pattern that was influenced by drift and introgression with surrounding populations, with important contributions from both males and females. We provide evidence that a sex-biased admixture with Europeans is probably associated with the founding of the Portuguese Gypsies.

Original language	English
Journal	American Journal of Physical Anthropology
Volume	148
Issue number	3
Pages (from-to)	389-94
Number of pages	6
ISSN	0002-9483
DOIs	https://doi.org/10.1002/ajpa.22061
Publication status	Published - Jul 2012

Keywords

Chromosomes, Human, X
Genetic Markers
Genetic Variation
Gypsies
Humans
INDEL Mutation
Linkage Disequilibrium
Male
Microsatellite Repeats
Portugal

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10.1002/ajpa.22061

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title = "Refining the genetic portrait of Portuguese Roma through X-chromosomal markers",

abstract = "Due to differences in transmission between X-chromosomal and autosomal DNA, the comparison of data derived from both markers allows deeper insight into the forces that shape the patterns of genetic diversity in populations. In this study, we applied this comparative approach to a sample of Portuguese Roma (Gypsies) by analyzing 43 X-chromosomal markers and 53 autosomal markers. Portuguese individuals of non-Gypsy ancestry were also studied. Compared with the host population, reduced levels of diversity on the X chromosome and autosomes were detected in Gypsies; this result was in line with known patterns of genetic diversity typical of Roma groups. As a consequence of the complex demographic past of the Roma, during which admixture and genetic drift played major roles, the amount of linkage disequilibrium (LD) on the X chromosome in Gypsies was considerably higher than that observed in non-Gypsies. When the pattern of differentiation on the X chromosome was compared with that of autosomes, there was evidence for asymmetries in female and male effective population sizes during the admixture between Roma and non-Roma. This result supplements previous data provided by mtDNA and the Y chromosome, underlining the importance of using combined information from the X chromosome and autosomes to dissect patterns of genetic diversity. Following the out-of-India dispersion, the Roma acquired a complex genetic pattern that was influenced by drift and introgression with surrounding populations, with important contributions from both males and females. We provide evidence that a sex-biased admixture with Europeans is probably associated with the founding of the Portuguese Gypsies.",

keywords = "Chromosomes, Human, X, Genetic Markers, Genetic Variation, Gypsies, Humans, INDEL Mutation, Linkage Disequilibrium, Male, Microsatellite Repeats, Portugal",

author = "Vania Pereira and Leonor Gusm{\~a}o and Cristina Valente and Rui Pereira and Jo{\~a}o Carneiro and Iva Gomes and Niels Morling and Ant{\'o}nio Amorim and {Jo{\~a}o Prata}, Maria",

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T1 - Refining the genetic portrait of Portuguese Roma through X-chromosomal markers

AU - Pereira, Vania

AU - Gusmão, Leonor

AU - Valente, Cristina

AU - Pereira, Rui

AU - Carneiro, João

AU - Gomes, Iva

AU - Morling, Niels

AU - Amorim, António

AU - João Prata, Maria

PY - 2012/7

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N2 - Due to differences in transmission between X-chromosomal and autosomal DNA, the comparison of data derived from both markers allows deeper insight into the forces that shape the patterns of genetic diversity in populations. In this study, we applied this comparative approach to a sample of Portuguese Roma (Gypsies) by analyzing 43 X-chromosomal markers and 53 autosomal markers. Portuguese individuals of non-Gypsy ancestry were also studied. Compared with the host population, reduced levels of diversity on the X chromosome and autosomes were detected in Gypsies; this result was in line with known patterns of genetic diversity typical of Roma groups. As a consequence of the complex demographic past of the Roma, during which admixture and genetic drift played major roles, the amount of linkage disequilibrium (LD) on the X chromosome in Gypsies was considerably higher than that observed in non-Gypsies. When the pattern of differentiation on the X chromosome was compared with that of autosomes, there was evidence for asymmetries in female and male effective population sizes during the admixture between Roma and non-Roma. This result supplements previous data provided by mtDNA and the Y chromosome, underlining the importance of using combined information from the X chromosome and autosomes to dissect patterns of genetic diversity. Following the out-of-India dispersion, the Roma acquired a complex genetic pattern that was influenced by drift and introgression with surrounding populations, with important contributions from both males and females. We provide evidence that a sex-biased admixture with Europeans is probably associated with the founding of the Portuguese Gypsies.

AB - Due to differences in transmission between X-chromosomal and autosomal DNA, the comparison of data derived from both markers allows deeper insight into the forces that shape the patterns of genetic diversity in populations. In this study, we applied this comparative approach to a sample of Portuguese Roma (Gypsies) by analyzing 43 X-chromosomal markers and 53 autosomal markers. Portuguese individuals of non-Gypsy ancestry were also studied. Compared with the host population, reduced levels of diversity on the X chromosome and autosomes were detected in Gypsies; this result was in line with known patterns of genetic diversity typical of Roma groups. As a consequence of the complex demographic past of the Roma, during which admixture and genetic drift played major roles, the amount of linkage disequilibrium (LD) on the X chromosome in Gypsies was considerably higher than that observed in non-Gypsies. When the pattern of differentiation on the X chromosome was compared with that of autosomes, there was evidence for asymmetries in female and male effective population sizes during the admixture between Roma and non-Roma. This result supplements previous data provided by mtDNA and the Y chromosome, underlining the importance of using combined information from the X chromosome and autosomes to dissect patterns of genetic diversity. Following the out-of-India dispersion, the Roma acquired a complex genetic pattern that was influenced by drift and introgression with surrounding populations, with important contributions from both males and females. We provide evidence that a sex-biased admixture with Europeans is probably associated with the founding of the Portuguese Gypsies.

KW - Chromosomes, Human, X

KW - Genetic Markers

KW - Genetic Variation

KW - Gypsies

KW - Humans

KW - INDEL Mutation

KW - Linkage Disequilibrium

KW - Male

KW - Microsatellite Repeats

KW - Portugal

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DO - 10.1002/ajpa.22061

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SP - 389

EP - 394

JO - American Journal of Physical Anthropology

JF - American Journal of Physical Anthropology

IS - 3

ER -

Refining the genetic portrait of Portuguese Roma through X-chromosomal markers

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Keywords

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