diff --git a/bseq.c b/bseq.c
index 6bf55f5..ec7dff3 100644
--- a/bseq.c
+++ b/bseq.c
@@ -62,7 +62,7 @@ static inline char *kstrdup(const kstring_t *s)
 	return t;
 }
 
-static inline void kseq2bseq(kseq_t *ks, mm_bseq1_t *s, int with_qual)
+static inline void kseq2bseq(kseq_t *ks, mm_bseq1_t *s, int with_qual, int with_comment)
 {
 	int i;
 	s->name = kstrdup(&ks->name);
@@ -71,10 +71,11 @@ static inline void kseq2bseq(kseq_t *ks, mm_bseq1_t *s, int with_qual)
 		if (s->seq[i] == 'u' || s->seq[i] == 'U')
 			--s->seq[i];
 	s->qual = with_qual && ks->qual.l? kstrdup(&ks->qual) : 0;
+	s->comment = with_comment && ks->comment.l? kstrdup(&ks->comment) : 0;
 	s->l_seq = ks->seq.l;
 }
 
-mm_bseq1_t *mm_bseq_read2(mm_bseq_file_t *fp, int chunk_size, int with_qual, int frag_mode, int *n_)
+mm_bseq1_t *mm_bseq_read3(mm_bseq_file_t *fp, int chunk_size, int with_qual, int with_comment, int frag_mode, int *n_)
 {
 	int64_t size = 0;
 	kvec_t(mm_bseq1_t) a = {0,0,0};
@@ -91,12 +92,12 @@ mm_bseq1_t *mm_bseq_read2(mm_bseq_file_t *fp, int chunk_size, int with_qual, int
 		assert(ks->seq.l <= INT32_MAX);
 		if (a.m == 0) kv_resize(mm_bseq1_t, 0, a, 256);
 		kv_pushp(mm_bseq1_t, 0, a, &s);
-		kseq2bseq(ks, s, with_qual);
+		kseq2bseq(ks, s, with_qual, with_comment);
 		size += s->l_seq;
 		if (size >= chunk_size) {
 			if (frag_mode && a.a[a.n-1].l_seq < CHECK_PAIR_THRES) {
 				while (kseq_read(ks) >= 0) {
-					kseq2bseq(ks, &fp->s, with_qual);
+					kseq2bseq(ks, &fp->s, with_qual, with_comment);
 					if (mm_qname_same(fp->s.name, a.a[a.n-1].name)) {
 						kv_push(mm_bseq1_t, 0, a, fp->s);
 						memset(&fp->s, 0, sizeof(mm_bseq1_t));
@@ -110,12 +111,17 @@ mm_bseq1_t *mm_bseq_read2(mm_bseq_file_t *fp, int chunk_size, int with_qual, int
 	return a.a;
 }
 
+mm_bseq1_t *mm_bseq_read2(mm_bseq_file_t *fp, int chunk_size, int with_qual, int frag_mode, int *n_)
+{
+	return mm_bseq_read3(fp, chunk_size, with_qual, 0, frag_mode, n_);
+}
+
 mm_bseq1_t *mm_bseq_read(mm_bseq_file_t *fp, int chunk_size, int with_qual, int *n_)
 {
 	return mm_bseq_read2(fp, chunk_size, with_qual, 0, n_);
 }
 
-mm_bseq1_t *mm_bseq_read_frag(int n_fp, mm_bseq_file_t **fp, int chunk_size, int with_qual, int *n_)
+mm_bseq1_t *mm_bseq_read_frag2(int n_fp, mm_bseq_file_t **fp, int chunk_size, int with_qual, int with_comment, int *n_)
 {
 	int i;
 	int64_t size = 0;
@@ -136,7 +142,7 @@ mm_bseq1_t *mm_bseq_read_frag(int n_fp, mm_bseq_file_t **fp, int chunk_size, int
 		for (i = 0; i < n_fp; ++i) {
 			mm_bseq1_t *s;
 			kv_pushp(mm_bseq1_t, 0, a, &s);
-			kseq2bseq(fp[i]->ks, s, with_qual);
+			kseq2bseq(fp[i]->ks, s, with_qual, with_comment);
 			size += s->l_seq;
 		}
 		if (size >= chunk_size) break;
@@ -145,6 +151,11 @@ mm_bseq1_t *mm_bseq_read_frag(int n_fp, mm_bseq_file_t **fp, int chunk_size, int
 	return a.a;
 }
 
+mm_bseq1_t *mm_bseq_read_frag(int n_fp, mm_bseq_file_t **fp, int chunk_size, int with_qual, int *n_)
+{
+	return mm_bseq_read_frag2(n_fp, fp, chunk_size, with_qual, 0, n_);
+}
+
 int mm_bseq_eof(mm_bseq_file_t *fp)
 {
 	return (ks_eof(fp->ks->f) && fp->s.seq == 0);
diff --git a/bseq.h b/bseq.h
index 09ae3da..2f25d3a 100644
--- a/bseq.h
+++ b/bseq.h
@@ -13,13 +13,15 @@ typedef struct mm_bseq_file_s mm_bseq_file_t;
 
 typedef struct {
 	int l_seq, rid;
-	char *name, *seq, *qual;
+	char *name, *seq, *qual, *comment;
 } mm_bseq1_t;
 
 mm_bseq_file_t *mm_bseq_open(const char *fn);
 void mm_bseq_close(mm_bseq_file_t *fp);
+mm_bseq1_t *mm_bseq_read3(mm_bseq_file_t *fp, int chunk_size, int with_qual, int with_comment, int frag_mode, int *n_);
 mm_bseq1_t *mm_bseq_read2(mm_bseq_file_t *fp, int chunk_size, int with_qual, int frag_mode, int *n_);
 mm_bseq1_t *mm_bseq_read(mm_bseq_file_t *fp, int chunk_size, int with_qual, int *n_);
+mm_bseq1_t *mm_bseq_read_frag2(int n_fp, mm_bseq_file_t **fp, int chunk_size, int with_qual, int with_comment, int *n_);
 mm_bseq1_t *mm_bseq_read_frag(int n_fp, mm_bseq_file_t **fp, int chunk_size, int with_qual, int *n_);
 int mm_bseq_eof(mm_bseq_file_t *fp);
 
diff --git a/format.c b/format.c
index 382dfd8..515a6b0 100644
--- a/format.c
+++ b/format.c
@@ -274,6 +274,8 @@ void mm_write_paf(kstring_t *s, const mm_idx_t *mi, const mm_bseq1_t *t, const m
 	}
 	if (r->p && (opt_flag & (MM_F_OUT_CS|MM_F_OUT_MD)))
 		write_cs_or_MD(km, s, mi, t, r, !(opt_flag&MM_F_OUT_CS_LONG), opt_flag&MM_F_OUT_MD);
+	if ((opt_flag & MM_F_COPY_COMMENT) && t->comment)
+		mm_sprintf_lite(s, "\t%s", t->comment);
 }
 
 static void sam_write_sq(kstring_t *s, char *seq, int l, int rev, int comp)
@@ -475,6 +477,9 @@ void mm_write_sam2(kstring_t *s, const mm_idx_t *mi, const mm_bseq1_t *t, int se
 			write_sam_cigar(s, flag, 1, t->l_seq, r, opt_flag);
 	}
 
+	if ((opt_flag & MM_F_COPY_COMMENT) && t->comment)
+		mm_sprintf_lite(s, "\t%s", t->comment);
+
 	s->s[s->l] = 0; // we always have room for an extra byte (see str_enlarge)
 }
 
diff --git a/main.c b/main.c
index 44dae53..a23866a 100644
--- a/main.c
+++ b/main.c
@@ -10,7 +10,7 @@
 #include "getopt.h"
 #endif
 
-#define MM_VERSION "2.9-r751-dirty"
+#define MM_VERSION "2.9-r752-dirty"
 
 #ifdef __linux__
 #include <sys/resource.h>
@@ -94,7 +94,7 @@ static inline void yes_or_no(mm_mapopt_t *opt, int flag, int long_idx, const cha
 
 int main(int argc, char *argv[])
 {
-	const char *opt_str = "2aSDw:k:K:t:r:f:Vv:g:G:I:d:XT:s:x:Hcp:M:n:z:A:B:O:E:m:N:Qu:R:hF:LC:";
+	const char *opt_str = "2aSDw:k:K:t:r:f:Vv:g:G:I:d:XT:s:x:Hcp:M:n:z:A:B:O:E:m:N:Qu:R:hF:LC:y";
 	mm_mapopt_t opt;
 	mm_idxopt_t ipt;
 	int i, c, n_threads = 3, long_idx;
@@ -140,6 +140,7 @@ int main(int argc, char *argv[])
 		else if (c == 'Q') opt.flag |= MM_F_NO_QUAL;
 		else if (c == 'Y') opt.flag |= MM_F_SOFTCLIP;
 		else if (c == 'L') opt.flag |= MM_F_LONG_CIGAR;
+		else if (c == 'y') opt.flag |= MM_F_COPY_COMMENT;
 		else if (c == 'T') opt.sdust_thres = atoi(optarg);
 		else if (c == 'n') opt.min_cnt = atoi(optarg);
 		else if (c == 'm') opt.min_chain_score = atoi(optarg);
@@ -272,6 +273,7 @@ int main(int argc, char *argv[])
 		fprintf(fp_help, "    -R STR       SAM read group line in a format like '@RG\\tID:foo\\tSM:bar' []\n");
 		fprintf(fp_help, "    -c           output CIGAR in PAF\n");
 		fprintf(fp_help, "    --cs[=STR]   output the cs tag; STR is 'short' (if absent) or 'long' [none]\n");
+		fprintf(fp_help, "    --MD         output the MD tag\n");
 		fprintf(fp_help, "    -Y           use soft clipping for supplementary alignments\n");
 		fprintf(fp_help, "    -t INT       number of threads [%d]\n", n_threads);
 		fprintf(fp_help, "    -K NUM       minibatch size for mapping [500M]\n");
diff --git a/map.c b/map.c
index 3146678..ebe4c61 100644
--- a/map.c
+++ b/map.c
@@ -442,11 +442,12 @@ static void *worker_pipeline(void *shared, int step, void *in)
     pipeline_t *p = (pipeline_t*)shared;
     if (step == 0) { // step 0: read sequences
 		int with_qual = (!!(p->opt->flag & MM_F_OUT_SAM) && !(p->opt->flag & MM_F_NO_QUAL));
+		int with_comment = !!(p->opt->flag & MM_F_COPY_COMMENT);
 		int frag_mode = (p->n_fp > 1 || !!(p->opt->flag & MM_F_FRAG_MODE));
         step_t *s;
         s = (step_t*)calloc(1, sizeof(step_t));
-		if (p->n_fp > 1) s->seq = mm_bseq_read_frag(p->n_fp, p->fp, p->mini_batch_size, with_qual, &s->n_seq);
-		else s->seq = mm_bseq_read2(p->fp[0], p->mini_batch_size, with_qual, frag_mode, &s->n_seq);
+		if (p->n_fp > 1) s->seq = mm_bseq_read_frag2(p->n_fp, p->fp, p->mini_batch_size, with_qual, with_comment, &s->n_seq);
+		else s->seq = mm_bseq_read3(p->fp[0], p->mini_batch_size, with_qual, with_comment, frag_mode, &s->n_seq);
 		if (s->seq) {
 			s->p = p;
 			for (i = 0; i < s->n_seq; ++i)
diff --git a/minimap.h b/minimap.h
index 399c5c4..7d416a1 100644
--- a/minimap.h
+++ b/minimap.h
@@ -30,6 +30,7 @@
 #define MM_F_HEAP_SORT     0x400000
 #define MM_F_ALL_CHAINS    0x800000
 #define MM_F_OUT_MD        0x1000000
+#define MM_F_COPY_COMMENT  0x2000000
 
 #define MM_I_HPC          0x1
 #define MM_I_NO_SEQ       0x2
diff --git a/minimap2.1 b/minimap2.1
index c37301e..0305b41 100644
--- a/minimap2.1
+++ b/minimap2.1
@@ -370,6 +370,9 @@ SAM read group line in a format like
 .B @RG\\\\tID:foo\\\\tSM:bar
 [].
 .TP
+.B -y
+Copy input FASTA/Q comments to output.
+.TP
 .B -c
 Generate CIGAR. In PAF, the CIGAR is written to the `cg' custom tag.
 .TP
diff --git a/test/MT-orang.fa b/test/MT-orang.fa
index ceb40ed..2919478 100644
--- a/test/MT-orang.fa
+++ b/test/MT-orang.fa
@@ -1,4 +1,4 @@
->MT_orang
+>MT_orang co:Z:comment
 GTTTATGTAGCTTATTCTATCCAAAGCAATGCACTGAAAATGTCTCGACGGGCCCACACG
 CCCCATAAACAAATAGGTTTGGTCCTAGCCTTTCTATTAGCTCTTAGTGAGGTTACACAT
 GCAAGCATCCCCGCCCCAGTGAGTCGCCCTCCAAGTCACTCTGACTAAGAGGAGCAAGCA