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Kaingang, Brazil (Rio das Cobras)

Study statistics

Loci
21 Autosomal STRs
Allele type
Unknown
Sample size
60
Location
Rio das Cobras, 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 60 0.229 1.670 0.700 0.617 0.560 0.771 0.428 0.491
D10S1248 60 0.227 1.430 0.650 0.594 0.530 0.773 0.355 0.936
D12S391 60 0.089 2.310 0.783 0.802 0.770 0.911 0.568 0.038
D13S317 60 0.116 1.760 0.717 0.722 0.690 0.884 0.455 0.210
D16S539 60 0.131 1.610 0.683 0.713 0.670 0.869 0.411 0.643
D18S51 59 0.100 1.970 0.746 0.745 0.720 0.900 0.503 0.697
D19S433 60 0.108 2.140 0.767 0.756 0.720 0.892 0.539 0.235
D1S1656 60 0.078 2.140 0.767 0.798 0.770 0.922 0.539 0.234
D21S11 60 0.109 1.790 0.717 0.714 0.700 0.891 0.462 0.548
D22S1045 60 0.394 1.050 0.517 0.487 0.380 0.606 0.210 0.479
D2S1338 60 0.098 2.730 0.817 0.788 0.760 0.902 0.630 0.129
D2S441 60 0.280 1.200 0.583 0.565 0.480 0.720 0.271 0.930
D3S1358 60 0.340 0.940 0.467 0.477 0.410 0.660 0.160 0.930
D5S818 60 0.203 1.500 0.667 0.642 0.590 0.797 0.379 0.203
D7S820 60 0.183 1.300 0.617 0.658 0.610 0.817 0.311 0.004
D8S1179 60 0.114 1.670 0.700 0.727 0.680 0.886 0.428 0.781
FGA 60 0.088 3.000 0.833 0.797 0.770 0.912 0.662 0.157
SE33 60 0.056 4.290 0.883 0.858 0.840 0.944 0.762 0.141
TH01 60 0.307 1.880 0.733 0.604 0.520 0.693 0.482 0.117
TPOX 60 0.140 1.330 0.617 0.696 0.650 0.860 0.319 0.190
vWA 60 0.324 1.070 0.533 0.525 0.430 0.676 0.218 0.482

Allele frequencies

CSF1PO D10S1248 D12S391 D13S317 D16S539 D18S51 D19S433 D1S1656 D21S11 D22S1045 D2S1338 D2S441 D3S1358 D5S818 D7S820 D8S1179 FGA SE33 TH01 TPOX vWA
5 0.008
6 0.108
7 0.008 0.283 0.458
8 0.025 0.408
9 0.45 0.367 0.058 0.033 0.017 0.017
10 0.242 0.075 0.117 0.383 0.308 0.058 0.05
11 0.2 0.025 0.092 0.325 0.034 0.533 0.508 0.483 0.033 0.242
11.3
12 0.533 0.008 0.125 0.183 0.042 0.008 0.025 0.125 0.075 0.067 0.275
12.2 0.033
13 0.025 0.083 0.208 0.008 0.203 0.125 0.158 0.025 0.075 0.383
13.2 0.308
14 0.55 0.05 0.424 0.033 0.158 0.058 0.308 0.025
14.2 0.017
15 0.308 0.017 0.333 0.1 0.6 0.667 0.15
15.2 0.142
15.3 0.008
16 0.017 0.1 0.153 0.083 0.392 0.275 0.567
16.2
16.3
17 0.034 0.033 0.008 0.225 0.058 0.125 0.392
17.3 0.35
18 0.025 0.076 0.05 0.058 0.017
18.3 0.025 0.108
19 0.275 0.292 0.033 0.05
20 0.233 0.083 0.017 0.108
20.3
21 0.217 0.008 0.017 0.167 0.008
22 0.033 0.008 0.092 0.133
23 0.092 0.242 0.05
24 0.283
24.2 0.008
25 0.267
25.2 0.058
26 0.042
26.2 0.033
27 0.033 0.008
27.2 0.225
28 0.083
28.2 0.183
29 0.058
29.2
30 0.483
30.2 0.142
31 0.025
31.2 0.025
32.2 0.092
33.2 0.175
35.1 0.025
36
43.2
53
63
93 0.417

Locus histograms

CSF1PO

D10S1248

D12S391

D13S317

D16S539

D18S51

D19S433

D1S1656

D21S11

D22S1045

D2S1338

D2S441

D3S1358

D5S818

D7S820

D8S1179

FGA

SE33

TH01

TPOX

vWA