diff --git a/align.c b/align.c
index c3b04d3..60bc08a 100644
--- a/align.c
+++ b/align.c
@@ -291,7 +291,7 @@ static void mm_append_cigar(mm_reg1_t *r, uint32_t n_cigar, uint32_t *cigar) //
 	}
 }
 
-static void mm_align_pair(void *km, const mm_mapopt_t *opt, int qlen, const uint8_t *qseq, int tlen, const uint8_t *tseq, const int8_t *mat, int w, int end_bonus, int zdrop, int flag, ksw_extz_t *ez)
+static void mm_align_pair(void *km, const mm_mapopt_t *opt, int qlen, const uint8_t *qseq, int tlen, const uint8_t *tseq, const uint8_t *junc, const int8_t *mat, int w, int end_bonus, int zdrop, int flag, ksw_extz_t *ez)
 {
 	if (mm_dbg_flag & MM_DBG_PRINT_ALN_SEQ) {
 		int i;
@@ -305,7 +305,7 @@ static void mm_align_pair(void *km, const mm_mapopt_t *opt, int qlen, const uint
 		ksw_reset_extz(ez);
 		ez->zdropped = 1;
 	} else if (opt->flag & MM_F_SPLICE)
-		ksw_exts2_sse(km, qlen, qseq, tlen, tseq, 5, mat, opt->q, opt->e, opt->q2, opt->noncan, zdrop, flag, ez);
+		ksw_exts2_sse(km, qlen, qseq, tlen, tseq, 5, mat, opt->q, opt->e, opt->q2, opt->noncan, zdrop, opt->junc_bonus, flag, junc, ez);
 	else if (opt->q == opt->q2 && opt->e == opt->e2)
 		ksw_extz2_sse(km, qlen, qseq, tlen, tseq, 5, mat, opt->q, opt->e, w, zdrop, end_bonus, flag, ez);
 	else
@@ -547,7 +547,7 @@ static void mm_align1(void *km, const mm_mapopt_t *opt, const mm_idx_t *mi, int
 {
 	int is_sr = !!(opt->flag & MM_F_SR), is_splice = !!(opt->flag & MM_F_SPLICE);
 	int32_t rid = a[r->as].x<<1>>33, rev = a[r->as].x>>63, as1, cnt1;
-	uint8_t *tseq, *qseq;
+	uint8_t *tseq, *qseq, *junc;
 	int32_t i, l, bw, dropped = 0, extra_flag = 0, rs0, re0, qs0, qe0;
 	int32_t rs, re, qs, qe;
 	int32_t rs1, qs1, re1, qe1;
@@ -666,13 +666,16 @@ static void mm_align1(void *km, const mm_mapopt_t *opt, const mm_idx_t *mi, int
 
 	assert(re0 > rs0);
 	tseq = (uint8_t*)kmalloc(km, re0 - rs0);
+	junc = (uint8_t*)kmalloc(km, re0 - rs0);
 
 	if (qs > 0 && rs > 0) { // left extension; probably the condition can be changed to "qs > qs0 && rs > rs0"
 		qseq = &qseq0[rev][qs0];
 		mm_idx_getseq(mi, rid, rs0, rs, tseq);
+		mm_idx_bed_junc(mi, rid, rs0, rs, junc);
 		mm_seq_rev(qs - qs0, qseq);
 		mm_seq_rev(rs - rs0, tseq);
-		mm_align_pair(km, opt, qs - qs0, qseq, rs - rs0, tseq, mat, bw, opt->end_bonus, r->split_inv? opt->zdrop_inv : opt->zdrop, extra_flag|KSW_EZ_EXTZ_ONLY|KSW_EZ_RIGHT|KSW_EZ_REV_CIGAR, ez);
+		mm_seq_rev(rs - rs0, junc);
+		mm_align_pair(km, opt, qs - qs0, qseq, rs - rs0, tseq, junc, mat, bw, opt->end_bonus, r->split_inv? opt->zdrop_inv : opt->zdrop, extra_flag|KSW_EZ_EXTZ_ONLY|KSW_EZ_RIGHT|KSW_EZ_REV_CIGAR, ez);
 		if (ez->n_cigar > 0) {
 			mm_append_cigar(r, ez->n_cigar, ez->cigar);
 			r->p->dp_score += ez->max;
@@ -698,6 +701,7 @@ static void mm_align1(void *km, const mm_mapopt_t *opt, const mm_idx_t *mi, int
 			// perform alignment
 			qseq = &qseq0[rev][qs];
 			mm_idx_getseq(mi, rid, rs, re, tseq);
+			mm_idx_bed_junc(mi, rid, rs, re, junc);
 			if (is_sr) { // perform ungapped alignment
 				assert(qe - qs == re - rs);
 				ksw_reset_extz(ez);
@@ -707,11 +711,11 @@ static void mm_align1(void *km, const mm_mapopt_t *opt, const mm_idx_t *mi, int
 				}
 				ez->cigar = ksw_push_cigar(km, &ez->n_cigar, &ez->m_cigar, ez->cigar, 0, qe - qs);
 			} else { // perform normal gapped alignment
-				mm_align_pair(km, opt, qe - qs, qseq, re - rs, tseq, mat, bw1, -1, opt->zdrop, extra_flag|KSW_EZ_APPROX_MAX, ez); // first pass: with approximate Z-drop
+				mm_align_pair(km, opt, qe - qs, qseq, re - rs, tseq, junc, mat, bw1, -1, opt->zdrop, extra_flag|KSW_EZ_APPROX_MAX, ez); // first pass: with approximate Z-drop
 			}
 			// test Z-drop and inversion Z-drop
 			if ((zdrop_code = mm_test_zdrop(km, opt, qseq, tseq, ez->n_cigar, ez->cigar, mat)) != 0)
-				mm_align_pair(km, opt, qe - qs, qseq, re - rs, tseq, mat, bw1, -1, zdrop_code == 2? opt->zdrop_inv : opt->zdrop, extra_flag, ez); // second pass: lift approximate
+				mm_align_pair(km, opt, qe - qs, qseq, re - rs, tseq, junc, mat, bw1, -1, zdrop_code == 2? opt->zdrop_inv : opt->zdrop, extra_flag, ez); // second pass: lift approximate
 			// update CIGAR
 			if (ez->n_cigar > 0)
 				mm_append_cigar(r, ez->n_cigar, ez->cigar);
@@ -737,7 +741,8 @@ static void mm_align1(void *km, const mm_mapopt_t *opt, const mm_idx_t *mi, int
 	if (!dropped && qe < qe0 && re < re0) { // right extension
 		qseq = &qseq0[rev][qe];
 		mm_idx_getseq(mi, rid, re, re0, tseq);
-		mm_align_pair(km, opt, qe0 - qe, qseq, re0 - re, tseq, mat, bw, opt->end_bonus, opt->zdrop, extra_flag|KSW_EZ_EXTZ_ONLY, ez);
+		mm_idx_bed_junc(mi, rid, re, re0, junc);
+		mm_align_pair(km, opt, qe0 - qe, qseq, re0 - re, tseq, junc, mat, bw, opt->end_bonus, opt->zdrop, extra_flag|KSW_EZ_EXTZ_ONLY, ez);
 		if (ez->n_cigar > 0) {
 			mm_append_cigar(r, ez->n_cigar, ez->cigar);
 			r->p->dp_score += ez->max;
@@ -760,6 +765,7 @@ static void mm_align1(void *km, const mm_mapopt_t *opt, const mm_idx_t *mi, int
 	}
 
 	kfree(km, tseq);
+	kfree(km, junc);
 }
 
 static int mm_align1_inv(void *km, const mm_mapopt_t *opt, const mm_idx_t *mi, int qlen, uint8_t *qseq0[2], const mm_reg1_t *r1, const mm_reg1_t *r2, mm_reg1_t *r_inv, ksw_extz_t *ez)
@@ -793,7 +799,7 @@ static int mm_align1_inv(void *km, const mm_mapopt_t *opt, const mm_idx_t *mi, i
 	mm_seq_rev(tl, tseq);
 	if (score < opt->min_dp_max) goto end_align1_inv;
 	q_off = ql - (q_off + 1), t_off = tl - (t_off + 1);
-	mm_align_pair(km, opt, ql - q_off, qseq + q_off, tl - t_off, tseq + t_off, mat, (int)(opt->bw * 1.5), -1, opt->zdrop, KSW_EZ_EXTZ_ONLY, ez);
+	mm_align_pair(km, opt, ql - q_off, qseq + q_off, tl - t_off, tseq + t_off, 0, mat, (int)(opt->bw * 1.5), -1, opt->zdrop, KSW_EZ_EXTZ_ONLY, ez);
 	if (ez->n_cigar == 0) goto end_align1_inv; // should never be here
 	mm_append_cigar(r_inv, ez->n_cigar, ez->cigar);
 	r_inv->p->dp_score = ez->max;
diff --git a/index.c b/index.c
index d842ec4..4b92fe6 100644
--- a/index.c
+++ b/index.c
@@ -668,7 +668,7 @@ int mm_idx_bed_read(mm_idx_t *mi, const char *fn)
 	return mi->I? 0 : -1;
 }
 
-int mm_idx_bed_junc(const mm_idx_t *mi, int32_t ctg, int32_t st, int32_t en, int32_t strand, int8_t *s)
+int mm_idx_bed_junc(const mm_idx_t *mi, int32_t ctg, int32_t st, int32_t en, uint8_t *s)
 {
 	int32_t i, left, right;
 	mm_idx_intv_t *r;
@@ -682,7 +682,7 @@ int mm_idx_bed_junc(const mm_idx_t *mi, int32_t ctg, int32_t st, int32_t en, int
 		else left = mid + 1;
 	}
 	for (i = left; i < r->n; ++i) {
-		if (st <= r->a[i].st && en >= r->a[i].en && r->a[i].strand != 0 && strand * r->a[i].strand >= 0) {
+		if (st <= r->a[i].st && en >= r->a[i].en && r->a[i].strand != 0) {
 			if (r->a[i].strand > 0) {
 				s[r->a[i].st] |= 1, s[r->a[i].en - 1] |= 2;
 			} else {
diff --git a/ksw2.h b/ksw2.h
index 213c27f..c700136 100644
--- a/ksw2.h
+++ b/ksw2.h
@@ -61,7 +61,7 @@ void ksw_extd2_sse(void *km, int qlen, const uint8_t *query, int tlen, const uin
 				   int8_t gapo, int8_t gape, int8_t gapo2, int8_t gape2, int w, int zdrop, int end_bonus, int flag, ksw_extz_t *ez);
 
 void ksw_exts2_sse(void *km, int qlen, const uint8_t *query, int tlen, const uint8_t *target, int8_t m, const int8_t *mat,
-				   int8_t gapo, int8_t gape, int8_t gapo2, int8_t noncan, int zdrop, int flag, ksw_extz_t *ez);
+				   int8_t gapo, int8_t gape, int8_t gapo2, int8_t noncan, int zdrop, int8_t junc_bonus, int flag, const uint8_t *junc, ksw_extz_t *ez);
 
 void ksw_extf2_sse(void *km, int qlen, const uint8_t *query, int tlen, const uint8_t *target, int8_t mch, int8_t mis, int8_t e, int w, int xdrop, ksw_extz_t *ez);
 
diff --git a/ksw2_dispatch.c b/ksw2_dispatch.c
index 22ca9bc..792b267 100644
--- a/ksw2_dispatch.c
+++ b/ksw2_dispatch.c
@@ -80,17 +80,17 @@ void ksw_extd2_sse(void *km, int qlen, const uint8_t *query, int tlen, const uin
 }
 
 void ksw_exts2_sse(void *km, int qlen, const uint8_t *query, int tlen, const uint8_t *target, int8_t m, const int8_t *mat,
-				   int8_t q, int8_t e, int8_t q2, int8_t noncan, int zdrop, int flag, ksw_extz_t *ez)
+				   int8_t q, int8_t e, int8_t q2, int8_t noncan, int zdrop, int8_t junc_bonus, int flag, const uint8_t *junc, ksw_extz_t *ez)
 {
 	extern void ksw_exts2_sse2(void *km, int qlen, const uint8_t *query, int tlen, const uint8_t *target, int8_t m, const int8_t *mat,
-				   int8_t q, int8_t e, int8_t q2, int8_t noncan, int zdrop, int flag, ksw_extz_t *ez);
+				   int8_t q, int8_t e, int8_t q2, int8_t noncan, int zdrop, int8_t junc_bonus, int flag, const uint8_t *junc, ksw_extz_t *ez);
 	extern void ksw_exts2_sse41(void *km, int qlen, const uint8_t *query, int tlen, const uint8_t *target, int8_t m, const int8_t *mat,
-				   int8_t q, int8_t e, int8_t q2, int8_t noncan, int zdrop, int flag, ksw_extz_t *ez);
+				   int8_t q, int8_t e, int8_t q2, int8_t noncan, int zdrop, int8_t junc_bonus, int flag, const uint8_t *junc, ksw_extz_t *ez);
 	if (ksw_simd < 0) ksw_simd = x86_simd();
 	if (ksw_simd & SIMD_SSE4_1)
-		ksw_exts2_sse41(km, qlen, query, tlen, target, m, mat, q, e, q2, noncan, zdrop, flag, ez);
+		ksw_exts2_sse41(km, qlen, query, tlen, target, m, mat, q, e, q2, noncan, zdrop, junc_bonus, flag, junc, ez);
 	else if (ksw_simd & SIMD_SSE2)
-		ksw_exts2_sse2(km, qlen, query, tlen, target, m, mat, q, e, q2, noncan, zdrop, flag, ez);
+		ksw_exts2_sse2(km, qlen, query, tlen, target, m, mat, q, e, q2, noncan, zdrop, junc_bonus, flag, junc, ez);
 	else abort();
 }
 #endif
diff --git a/ksw2_exts2_sse.c b/ksw2_exts2_sse.c
index 308f491..f025838 100644
--- a/ksw2_exts2_sse.c
+++ b/ksw2_exts2_sse.c
@@ -17,14 +17,14 @@
 #ifdef KSW_CPU_DISPATCH
 #ifdef __SSE4_1__
 void ksw_exts2_sse41(void *km, int qlen, const uint8_t *query, int tlen, const uint8_t *target, int8_t m, const int8_t *mat,
-				   int8_t q, int8_t e, int8_t q2, int8_t noncan, int zdrop, int flag, ksw_extz_t *ez)
+				   int8_t q, int8_t e, int8_t q2, int8_t noncan, int zdrop, int8_t junc_bonus, int flag, const uint8_t *junc, ksw_extz_t *ez)
 #else
 void ksw_exts2_sse2(void *km, int qlen, const uint8_t *query, int tlen, const uint8_t *target, int8_t m, const int8_t *mat,
-				   int8_t q, int8_t e, int8_t q2, int8_t noncan, int zdrop, int flag, ksw_extz_t *ez)
+				   int8_t q, int8_t e, int8_t q2, int8_t noncan, int zdrop, int8_t junc_bonus, int flag, const uint8_t *junc, ksw_extz_t *ez)
 #endif
 #else
 void ksw_exts2_sse(void *km, int qlen, const uint8_t *query, int tlen, const uint8_t *target, int8_t m, const int8_t *mat,
-				   int8_t q, int8_t e, int8_t q2, int8_t noncan, int zdrop, int flag, ksw_extz_t *ez)
+				   int8_t q, int8_t e, int8_t q2, int8_t noncan, int zdrop, int8_t junc_bonus, int flag, const uint8_t *junc, ksw_extz_t *ez)
 #endif // ~KSW_CPU_DISPATCH
 {
 #define __dp_code_block1 \
@@ -120,6 +120,10 @@ void ksw_exts2_sse(void *km, int qlen, const uint8_t *query, int tlen, const uin
 			if (can_type && (target[t+3] == 0 || target[t+3] == 2)) can_type = 2;
 			if (can_type) ((int8_t*)donor)[t] = can_type == 2? 0 : semi_cost;
 		}
+		if (junc)
+			for (t = 0; t < tlen - 1; ++t)
+				if (((flag & KSW_EZ_SPLICE_FOR) && (junc[t+1]&1)) || ((flag & KSW_EZ_SPLICE_REV) && (junc[t+1]&2)))
+					((int8_t*)donor)[t] += junc_bonus;
 		memset(acceptor, -noncan, tlen_ * 16);
 		for (t = 2; t < tlen; ++t) {
 			int can_type = 0;
@@ -128,6 +132,10 @@ void ksw_exts2_sse(void *km, int qlen, const uint8_t *query, int tlen, const uin
 			if (can_type && (target[t-2] == 1 || target[t-2] == 3)) can_type = 2;
 			if (can_type) ((int8_t*)acceptor)[t] = can_type == 2? 0 : semi_cost;
 		}
+		if (junc)
+			for (t = 0; t < tlen; ++t)
+				if (((flag & KSW_EZ_SPLICE_FOR) && (junc[t]&2)) || ((flag & KSW_EZ_SPLICE_REV) && (junc[t]&1)))
+					((int8_t*)acceptor)[t] += junc_bonus;
 	}
 
 	for (r = 0, last_st = last_en = -1; r < qlen + tlen - 1; ++r) {
diff --git a/minimap.h b/minimap.h
index 947efe1..358cad7 100644
--- a/minimap.h
+++ b/minimap.h
@@ -128,6 +128,7 @@ typedef struct {
 	int a, b, q, e, q2, e2; // matching score, mismatch, gap-open and gap-ext penalties
 	int sc_ambi; // score when one or both bases are "N"
 	int noncan;      // cost of non-canonical splicing sites
+	int junc_bonus;
 	int zdrop, zdrop_inv;   // break alignment if alignment score drops too fast along the diagonal
 	int end_bonus;
 	int min_dp_max;  // drop an alignment if the score of the max scoring segment is below this threshold
@@ -367,7 +368,7 @@ int mm_idx_name2id(const mm_idx_t *mi, const char *name);
 int mm_idx_getseq(const mm_idx_t *mi, uint32_t rid, uint32_t st, uint32_t en, uint8_t *seq);
 
 int mm_idx_bed_read(mm_idx_t *mi, const char *fn);
-int mm_idx_bed_junc(const mm_idx_t *mi, int32_t ctg, int32_t st, int32_t en, int32_t strand, int8_t *s);
+int mm_idx_bed_junc(const mm_idx_t *mi, int32_t ctg, int32_t st, int32_t en, uint8_t *s);
 
 // deprecated APIs for backward compatibility
 void mm_mapopt_init(mm_mapopt_t *opt);
diff --git a/options.c b/options.c
index eac73e3..ac1e5e1 100644
--- a/options.c
+++ b/options.c
@@ -126,6 +126,7 @@ int mm_set_opt(const char *preset, mm_idxopt_t *io, mm_mapopt_t *mo)
 		mo->max_gap = 2000, mo->max_gap_ref = mo->bw = 200000;
 		mo->a = 1, mo->b = 2, mo->q = 2, mo->e = 1, mo->q2 = 32, mo->e2 = 0;
 		mo->noncan = 9;
+		mo->junc_bonus = 9;
 		mo->zdrop = 200, mo->zdrop_inv = 100; // because mo->a is halved
 	} else return -1;
 	return 0;
diff --git a/python/cmappy.pxd b/python/cmappy.pxd
index 1bbe749..ba1871d 100644
--- a/python/cmappy.pxd
+++ b/python/cmappy.pxd
@@ -29,6 +29,7 @@ cdef extern from "minimap.h":
 		int a, b, q, e, q2, e2
 		int sc_ambi
 		int noncan
+		int junc_bonus
 		int zdrop, zdrop_inv
 		int end_bonus
 		int min_dp_max