Spatial and temporal variation in the kdr allele L1014S in Anopheles gambiae s.s. and phenotypic variability in susceptibility to insecticides in Western Kenya

Table 1 Genotype frequencies for kdr 1014S in Anopheles gambiae s.s. according location and date of sample collection.

Location	Year/Month^a	Sample Size	Genotype Counts^bS/S S/E E/E			*kdr* Homo- zygosity	S.E.	F_IS^c
Asembo	1996	95	85	10	0	0.0	--	-0.0503
	2000	27	27	0	0	0.0	--	--
	2004	126	69	41	16†	12.7	2.98	0.2053*
	2005	98	42	39	17	17.4	3.94	0.1537
	2007	20	7	6	7	35.0	10.94	0.4213
	2008	56	13	6	37‡	66.1	6.38	0.7416***
	2009	36	2	1	33†	91.7	4.67	0.7904**
	2010	8	0	0	8	100	0.00	--
Seme	2000	30	27	3	0	0.0	--	-0.0357
	2003	130	102	23	5†	3.8	1.69	0.1934*
	2005	116	50	52	14	12.1	3.04	0.0122
	2007	16	6	5	5	31.2	11.97	0.4000
	2008	41	5	3	33‡	80.5	6.27	0.7315***
Busia	2009/Apr	129	11	15	103‡	79.8	3.55	0.5295***
	2009/May	107	0	5	102	95.3	2.05	-0.0192
	2009/Jul	76	1	1	74†	97.4	1.85	0.6637*
	2010/May	134	0	3	131	97.8	1.28	-0.0076
Malaba	2009/May	378	2	25	351	92.9	1.33	0.1049
	2009/Jul	83	0	3	80	96.4	2.06	-0.0123
Bungoma	2009/May	38	0	1	37	97.4	2.63	--
	2009/Oct	100	3	3	94‡	94.0	2.39	0.6538***
	2009/Nov	36	1	2	33	91.7	4.67	0.4815
	2010/May	152	4	1	147	96.7	1.45	0.8862***
Kakamega	2009/Apr	67	1	2	64†	95.5	2.55	0.4903*
	2009/May	22	1	1	20	90.9	6.27	0.6557
	2009/Jul	39	0	1	38	97.4	2.56	--
	2009/Sep	46	2	0	44‡	95.6	3.04	1.0000***
	2010/May	38	0	1	37	97.4	2.63	--
Kisian	2009/Feb	27	0	1	26	96.3	3.70	--
	2009/Jun	27	1	1	25†	92.6	5.14	0.6579*
	2010/May	33	0	0	33	100.0	0.00	--

^aYear of sample collection only is given for the kdr time series for Asembo and Seme although sampling was typically performed during the peak of the rainy season in May or June. Month of sampling is given for the 2009 and 2010 collections from sites across western Kenya.
^bThree possible kdr genotypes are S/S, S/E, and EE, where S represents the susceptible wild type allele and E (for East African) represents the L1014S allele. The symbols † and ‡ indicate that genotype frequencies depart from Hardy-Weinberg expectations, although those with † are no longer significant following a Bonferroni correction for multiple tests
^cF_IS values > 0 indicate heterozygote deficiency, while values < 0 indicate heterozygote excess. A double dash (--) indicates values that were undefined. Significance level indicates rejection of the null hypothesis F_IS = 0, where *, **, and *** indicate p < 0.05, p < 0.01, and p < 0.001, respectively. After a Bonferroni correction for multiple tests, only those values with *** remain significant at the corrected significance level (α = 0.0017).

ISSN: 1475-2875