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Guarani M’byá (Brazilian Amerindian), Brazil

Study statistics

Loci
21 Autosomal STRs
Allele type
Unknown
Sample size
51
Population
Guarani M’byá (Brazilian Amerindian)
More studies with this population
Location
Southern Brazil
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Bibliographic information

Date published
Feb. 12, 2022
Title
Population structure and forensic genetic analyses in Guarani and Kaingang Amerindian populations from Brazil
Authors
Claudia Marina Schellin-Becker, Verónica Calonga-Solís, Marcelo Malaghini, Luiza Rauen Sabbag, Maria Luiza Petzl-Erler, Danillo G Augusto, and Danielle Malheiros
Journal
Forensic Science International: Genetics
Abstract

When DNA profile comparisons between a crime scene trace and a reference sample generate correspondence, the match probability has to be estimated, so that evaluation of the strength of the forensic DNA evidence can be made. The random match probability estimations require information on allele frequencies and an adjustment factor, referred to as theta (θ) or Fst, a co-ancestry correction factor for subpopulation effects. The θ value has been standardized for urban and isolated populations, but inconsistencies have been reported when it is specifically calculated for smaller and isolated populations, including Amerindian populations. Notably, attempts to characterize forensic markers of these minor populations have been extensively limited and more conservative estimates of the correction factor may be generated for each of them. Therefore, we estimate allele frequencies of 21 autosomal STR markers used for forensic testing and calculated relevant forensic parameters for the set. In addition, we featured the possible structure of five Brazilian Amerindian populations that have been genetically isolated for centuries so we could obtain the appropriate θ value for them. The sample consisted of 319 individuals: (1) 121 Kaingang, from two communities: Ivaí (KIV=61) and Rio das Cobras (KRC=60); and (2) 198 Guaranis from three communities: Mbya from Rio das Cobras (GRC=51), Guarani Ñandeva (GND=71) and Guarani Kaiowá (GKW=76). Between Guarani populations low (Rst=0.0402, p < 10−4) to high (Rst=0.1557, p < 10−5) differentiation was found. Regarding Guarani and Kaingang populations, intermediate (Rst=0.0590, p < 10−5) to high (Rst=0.1604, p < 10−5) differentiation was found. The two Kaingang populations showed very low differentiation between them (Rst=0.0017, p = 0.27), which justifies the union of both genetic data for forensic databases and calculations. The combined power of discrimination (PD) and the combined power of exclusion (PE) were calculated for each population, demonstrating the usefulness of this set of markers in forensic and kinship analysis regarding these populations. Considering the demographic heterogeneity of Amerindian populations in general, the Fst mean value (0.03) was evaluated regarding 43 different indigenous populations from the Americas, including Guaranis and Kaingangs. This result confirms the adequacy of the standardized θ value for the forensic random match probability estimations involving Amerindian populations.

Forensic parameters

Forensic parameters for each locus as reported by the authors.
Locus # MP PI Hobs Hexp PIC PD PE HWE
CSF1PO 51 0.216 1.700 0.706 0.629 0.560 0.784 0.437 0.317
D10S1248 51 0.179 1.590 0.686 0.677 0.610 0.821 0.407 0.763
D12S391 50 0.135 1.670 0.700 0.727 0.680 0.865 0.428 0.246
D13S317 51 0.103 1.960 0.745 0.765 0.730 0.897 0.501 0.273
D16S539 51 0.107 2.170 0.765 0.753 0.720 0.893 0.543 0.455
D18S51 51 0.133 1.060 0.529 0.707 0.660 0.867 0.215 0.022
D19S433 51 0.303 0.800 0.373 0.508 0.470 0.697 0.098 0.072
D1S1656 51 0.103 1.820 0.725 0.755 0.720 0.897 0.469 0.176
D21S11 51 0.106 1.860 0.725 0.750 0.720 0.894 0.477 0.822
D22S1045 51 0.470 1.080 0.529 0.423 0.340 0.530 0.223 0.105
D2S1338 51 0.103 2.320 0.784 0.757 0.720 0.897 0.570 0.996
D2S441 51 0.632 0.610 0.176 0.230 0.220 0.368 0.024 0.036
D3S1358 51 0.288 1.280 0.608 0.572 0.500 0.712 0.300 0.115
D5S818 51 0.266 0.850 0.412 0.554 0.470 0.734 0.121 0.091
D7S820 51 0.205 1.060 0.529 0.606 0.540 0.795 0.215 0.593
D8S1179 51 0.158 1.500 0.667 0.676 0.630 0.842 0.379 0.104
FGA 51 0.061 2.830 0.824 0.835 0.810 0.939 0.643 0.601
SE33 51 0.073 1.700 0.706 0.817 0.790 0.927 0.437 0.044
TH01 51 0.180 1.280 0.608 0.664 0.590 0.820 0.300 0.604
TPOX 51 0.198 1.300 0.608 0.638 0.580 0.802 0.310 0.446
vWA 51 0.159 1.820 0.725 0.670 0.630 0.841 0.469 0.863

Allele frequencies

CSF1PO D10S1248 D12S391 D13S317 D16S539 D18S51 D19S433 D1S1656 D21S11 D22S1045 D2S1338 D2S441 D3S1358 D5S818 D7S820 D8S1179 FGA SE33 TH01 TPOX vWA
5
6 0.343
7 0.343 0.294
8 0.01 0.01 0.245
9 0.176 0.039 0.088
10 0.167 0.039 0.294 0.029 0.873 0.01 0.039 0.069
11 0.304 0.363 0.176 0.02 0.078 0.569 0.529 0.127 0.471
11.3
12 0.5 0.196 0.333 0.314 0.01 0.01 0.01 0.324 0.01 0.284
12.2 0.02
13 0.029 0.294 0.176 0.127 0.196 0.667 0.118 0.069 0.01 0.265
13.2 0.02
14 0.353 0.039 0.392 0.206 0.029 0.049 0.48 0.02
14.2
15 0.333 0.029 0.02 0.059 0.373 0.696 0.333 0.049 0.186
15.2
15.3
16 0.02 0.029 0.02 0.049 0.304 0.559 0.275 0.176
16.2
16.3
17 0.01 0.353 0.039 0.029 0.5
17.3 0.265
18 0.06 0.157 0.049 0.078 0.118
18.3 0.137
19 0.39 0.078 0.02 0.088 0.01
20 0.24 0.167 0.01 0.059
20.3
21 0.08 0.118
22 0.23 0.078
23 0.01 0.245 0.255
24 0.167
24.2
25 0.196
25.2
26 0.078
26.2
27 0.01
27.2 0.029
28 0.01 0.108
28.2 0.245
29 0.265
29.2 0.01
30 0.363
30.2 0.157
31 0.137
31.2 0.029
32.2 0.167
33.2 0.029
35.1
36
43.2
53
63
93 0.363

Locus histograms

CSF1PO

D10S1248

D12S391

D13S317

D16S539

D18S51

D19S433

D1S1656

D21S11

D22S1045

D2S1338

D2S441

D3S1358

D5S818

D7S820

D8S1179

FGA

SE33

TH01

TPOX

vWA