diff --git a/bwamem.c b/bwamem.c
index 5ee153a..8d15f15 100644
--- a/bwamem.c
+++ b/bwamem.c
@@ -1036,7 +1036,13 @@ mem_alnreg_v mem_align1_core(const mem_opt_t *opt, const bwt_t *bwt, const bntse
 	regs.n = mem_sort_and_dedup(regs.n, regs.a, opt->mask_level_redun);
 	if (opt->flag & MEM_F_NO_EXACT)
 		regs.n = mem_test_and_remove_exact(opt, regs.n, regs.a, l_seq);
-	if (bwa_verbose >= 4) err_printf("* %ld chains remain after removing duplicated chains\n", regs.n);
+	if (bwa_verbose >= 4) {
+		err_printf("* %ld chains remain after removing duplicated chains\n", regs.n);
+		for (i = 0; i < regs.n; ++i) {
+			mem_alnreg_t *p = &regs.a[i];
+			printf("** %d, [%d,%d) <=> [%ld,%ld)\n", p->score, p->qb, p->qe, (long)p->rb, (long)p->re);
+		}
+	}
 	return regs;
 }
 
diff --git a/fastmap.c b/fastmap.c
index c971f9b..8ffa07b 100644
--- a/fastmap.c
+++ b/fastmap.c
@@ -18,6 +18,22 @@ extern unsigned char nst_nt4_table[256];
 void *kopen(const char *fn, int *_fd);
 int kclose(void *a);
 
+static void update_a(mem_opt_t *opt, const mem_opt_t *opt0)
+{
+	if (opt0->a) { // matching score is changed
+		if (!opt0->b) opt->b *= opt->a;
+		if (!opt0->T) opt->T *= opt->a;
+		if (!opt0->o_del) opt->o_del *= opt->a;
+		if (!opt0->e_del) opt->e_del *= opt->a;
+		if (!opt0->o_ins) opt->o_ins *= opt->a;
+		if (!opt0->e_ins) opt->e_ins *= opt->a;
+		if (!opt0->zdrop) opt->zdrop *= opt->a;
+		if (!opt0->pen_clip5) opt->pen_clip5 *= opt->a;
+		if (!opt0->pen_clip3) opt->pen_clip3 *= opt->a;
+		if (!opt0->pen_unpaired) opt->pen_unpaired *= opt->a;
+	}
+}
+
 int main_mem(int argc, char *argv[])
 {
 	mem_opt_t *opt, opt0;
@@ -27,6 +43,7 @@ int main_mem(int argc, char *argv[])
 	bseq1_t *seqs;
 	bwaidx_t *idx;
 	char *p, *rg_line = 0;
+	const char *mode = 0;
 	void *ko = 0, *ko2 = 0;
 	int64_t n_processed = 0;
 	mem_pestat_t pes[4], *pes0 = 0;
@@ -35,11 +52,11 @@ int main_mem(int argc, char *argv[])
 	for (i = 0; i < 4; ++i) pes[i].failed = 1;
 
 	opt = mem_opt_init();
-	opt0.a = opt0.b = opt0.o_del = opt0.e_del = opt0.o_ins = opt0.e_ins = opt0.pen_unpaired = -1;
-	opt0.pen_clip5 = opt0.pen_clip3 = opt0.zdrop = opt0.T = -1;
-	while ((c = getopt(argc, argv, "epaMCSPHk:c:v:s:r:t:R:A:B:O:E:U:w:L:d:T:Q:D:m:I:N:W:")) >= 0) {
-		if (c == 'k') opt->min_seed_len = atoi(optarg);
-		else if (c == 'w') opt->w = atoi(optarg);
+	memset(&opt0, 0, sizeof(mem_opt_t));
+	while ((c = getopt(argc, argv, "epaMCSPHk:c:v:s:r:t:R:A:B:O:E:U:w:L:d:T:Q:D:m:I:N:W:x:")) >= 0) {
+		if (c == 'k') opt->min_seed_len = atoi(optarg), opt0.min_seed_len = 1;
+		else if (c == 'x') mode = optarg;
+		else if (c == 'w') opt->w = atoi(optarg), opt0.w = 1;
 		else if (c == 'A') opt->a = atoi(optarg), opt0.a = 1;
 		else if (c == 'B') opt->b = atoi(optarg), opt0.b = 1;
 		else if (c == 'T') opt->T = atoi(optarg), opt0.T = 1;
@@ -51,17 +68,18 @@ int main_mem(int argc, char *argv[])
 		else if (c == 'M') opt->flag |= MEM_F_NO_MULTI;
 		else if (c == 'S') opt->flag |= MEM_F_NO_RESCUE;
 		else if (c == 'e') opt->flag |= MEM_F_NO_EXACT;
-		else if (c == 'c') opt->max_occ = atoi(optarg);
+		else if (c == 'c') opt->max_occ = atoi(optarg), opt0.max_occ = 1;
 		else if (c == 'd') opt->zdrop = atoi(optarg), opt0.zdrop = 1;
 		else if (c == 'v') bwa_verbose = atoi(optarg);
-		else if (c == 'r') opt->split_factor = atof(optarg);
-		else if (c == 'D') opt->chain_drop_ratio = atof(optarg);
-		else if (c == 'm') opt->max_matesw = atoi(optarg);
-		else if (c == 's') opt->split_width = atoi(optarg);
-		else if (c == 'N') opt->max_chain_gap = atoi(optarg);
-		else if (c == 'W') opt->min_chain_weight = atoi(optarg);
+		else if (c == 'r') opt->split_factor = atof(optarg), opt0.split_factor = 1.;
+		else if (c == 'D') opt->chain_drop_ratio = atof(optarg), opt0.chain_drop_ratio = 1.;
+		else if (c == 'm') opt->max_matesw = atoi(optarg), opt0.max_matesw = 1;
+		else if (c == 's') opt->split_width = atoi(optarg), opt0.split_width = 1;
+		else if (c == 'N') opt->max_chain_gap = atoi(optarg), opt0.max_chain_gap = 1;
+		else if (c == 'W') opt->min_chain_weight = atoi(optarg), opt0.min_chain_weight = 1;
 		else if (c == 'C') copy_comment = 1;
 		else if (c == 'Q') {
+			opt0.mapQ_coef_len = 1;
 			opt->mapQ_coef_len = atoi(optarg);
 			opt->mapQ_coef_fac = opt->mapQ_coef_len > 0? log(opt->mapQ_coef_len) : 0;
 		} else if (c == 'O') {
@@ -102,7 +120,6 @@ int main_mem(int argc, char *argv[])
 		else return 1;
 	}
 	if (opt->n_threads < 1) opt->n_threads = 1;
-//	if (opt->T < opt->min_HSP_score) opt->T = opt->min_HSP_score; // TODO: tie ->T to MEM_HSP_COEF
 	if (optind + 1 >= argc || optind + 3 < argc) {
 		fprintf(stderr, "\n");
 		fprintf(stderr, "Usage: bwa mem [options] <idxbase> <in1.fq> [in2.fq]\n\n");
@@ -115,16 +132,19 @@ int main_mem(int argc, char *argv[])
 //		fprintf(stderr, "       -s INT        look for internal seeds inside a seed with less than INT occ [%d]\n", opt->split_width);
 		fprintf(stderr, "       -c INT        skip seeds with more than INT occurrences [%d]\n", opt->max_occ);
 		fprintf(stderr, "       -D FLOAT      drop chains shorter than FLOAT fraction of the longest overlapping chain [%.2f]\n", opt->chain_drop_ratio);
+		fprintf(stderr, "       -W INT        discard a chain if seeded bases shorter than INT [0]\n");
 		fprintf(stderr, "       -m INT        perform at most INT rounds of mate rescues for each read [%d]\n", opt->max_matesw);
 		fprintf(stderr, "       -S            skip mate rescue\n");
 		fprintf(stderr, "       -P            skip pairing; mate rescue performed unless -S also in use\n");
 		fprintf(stderr, "       -e            discard full-length exact matches\n");
-		fprintf(stderr, "       -A INT        score for a sequence match, which scales [-TdBOELU] unless overridden [%d]\n", opt->a);
+		fprintf(stderr, "       -A INT        score for a sequence match, which scales options -TdBOELU unless overridden [%d]\n", opt->a);
 		fprintf(stderr, "       -B INT        penalty for a mismatch [%d]\n", opt->b);
 		fprintf(stderr, "       -O INT[,INT]  gap open penalties for deletions and insertions [%d,%d]\n", opt->o_del, opt->o_ins);
 		fprintf(stderr, "       -E INT[,INT]  gap extension penalty; a gap of size k cost '{-O} + {-E}*k' [%d,%d]\n", opt->e_del, opt->e_ins);
 		fprintf(stderr, "       -L INT[,INT]  penalty for 5'- and 3'-end clipping [%d,%d]\n", opt->pen_clip5, opt->pen_clip3);
 		fprintf(stderr, "       -U INT        penalty for an unpaired read pair [%d]\n", opt->pen_unpaired);
+		fprintf(stderr, "       -x STR        read type. Setting -x changes multiple parameters unless overriden [null]\n");
+		fprintf(stderr, "                     pacbio: -k17 -W40 -w200 -c1000 -r10 -A2 -B7 -O2 -E1 -L0\n");
 		fprintf(stderr, "\nInput/output options:\n\n");
 		fprintf(stderr, "       -p            first query file consists of interleaved paired-end sequences\n");
 		fprintf(stderr, "       -R STR        read group header line such as '@RG\\tID:foo\\tSM:bar' [null]\n");
@@ -140,25 +160,35 @@ int main_mem(int argc, char *argv[])
 		fprintf(stderr, "                     FR orientation only. [inferred]\n");
 		fprintf(stderr, "\n");
 		fprintf(stderr, "Note: Please read the man page for detailed description of the command line and options.\n");
-		fprintf(stderr, "      `-k17 -W40 -w200 -c1000 -r10 -A2 -O2 -E1' is recommended for PacBio reads as of early 2014.\n");
 		fprintf(stderr, "\n");
 		free(opt);
 		return 1;
 	}
 
-	if (opt0.a == 1) { // matching score is changed
-		if (opt0.b != 1) opt->b *= opt->a;
-		if (opt0.T != 1) opt->T *= opt->a;
-		if (opt0.o_del != 1) opt->o_del *= opt->a;
-		if (opt0.e_del != 1) opt->e_del *= opt->a;
-		if (opt0.o_ins != 1) opt->o_ins *= opt->a;
-		if (opt0.e_ins != 1) opt->e_ins *= opt->a;
-		if (opt0.zdrop != 1) opt->zdrop *= opt->a;
-		if (opt0.pen_clip5 != 1) opt->pen_clip5 *= opt->a;
-		if (opt0.pen_clip3 != 1) opt->pen_clip3 *= opt->a;
-		if (opt0.pen_unpaired != 1) opt->pen_unpaired *= opt->a;
-	}
+	if (mode) {
+		if (strcmp(mode, "pacbio") == 0) {
+			if (!opt0.a) opt->a = 2, opt0.a = 1;
+			update_a(opt, &opt0);
+			if (!opt0.b) opt->b = 7;
+			if (!opt0.o_del) opt->o_del = 2;
+			if (!opt0.e_del) opt->e_del = 1;
+			if (!opt0.o_ins) opt->o_ins = 2;
+			if (!opt0.e_ins) opt->e_ins = 1;
+			if (!opt0.w) opt->w = 200;
+			if (!opt0.min_seed_len) opt->min_seed_len = 17;
+			if (!opt0.min_chain_weight) opt->min_chain_weight = 40;
+			if (!opt0.max_occ) opt->max_occ = 1000;
+			if (!opt0.pen_clip5) opt->pen_clip5 = 0;
+			if (!opt0.pen_clip3) opt->pen_clip3 = 0;
+			if (opt0.split_factor == 0.) opt->split_factor = 10.;
+		} else {
+			fprintf(stderr, "[E::%s] unknown read type '%s'\n", __func__, mode);
+			return 1; // FIXME memory leak
+		}
+	} else update_a(opt, &opt0);
+//	if (opt->T < opt->min_HSP_score) opt->T = opt->min_HSP_score; // TODO: tie ->T to MEM_HSP_COEF
 	bwa_fill_scmat(opt->a, opt->b, opt->mat);
+
 	if ((idx = bwa_idx_load(argv[optind], BWA_IDX_ALL)) == 0) return 1; // FIXME: memory leak
 
 	ko = kopen(argv[optind + 1], &fd);
diff --git a/main.c b/main.c
index 1089477..dd06b42 100644
--- a/main.c
+++ b/main.c
@@ -4,7 +4,7 @@
 #include "utils.h"
 
 #ifndef PACKAGE_VERSION
-#define PACKAGE_VERSION "0.7.8+dev-r462"
+#define PACKAGE_VERSION "0.7.8+dev-r463"
 #endif
 
 int bwa_fa2pac(int argc, char *argv[]);