diff --git a/datastore/genera.go b/datastore/genera.go
index a497168..746e1af 100644
--- a/datastore/genera.go
+++ b/datastore/genera.go
@@ -8,7 +8,7 @@ import (
 )
 
 func init() {
-	DB.AddTableWithName(models.Genus{}, "genera").SetKeys(true, "Id")
+	DB.AddTableWithName(models.GenusBase{}, "genera").SetKeys(true, "Id")
 }
 
 type generaStore struct {
@@ -17,7 +17,8 @@ type generaStore struct {
 
 func (s *generaStore) Get(id int64) (*models.Genus, error) {
 	var genus models.Genus
-	if err := s.dbh.SelectOne(&genus, `SELECT * FROM genera WHERE id=$1;`, id); err != nil {
+	err := s.dbh.SelectOne(&genus, `SELECT g.*, array_agg(s.id) AS species FROM genera g LEFT OUTER JOIN species s ON s.genus_id=g.id WHERE g.id=$1 GROUP BY g.id;`, id)
+	if err != nil {
 		return nil, err
 	}
 	if &genus == nil {
@@ -30,11 +31,14 @@ func (s *generaStore) Create(genus *models.Genus) (bool, error) {
 	currentTime := time.Now()
 	genus.CreatedAt = currentTime
 	genus.UpdatedAt = currentTime
-	if err := s.dbh.Insert(genus); err != nil {
+	// Ugly --- extract embedded struct
+	base := genus.GenusBase
+	if err := s.dbh.Insert(base); err != nil {
 		if strings.Contains(err.Error(), `violates unique constraint "genus_idx"`) {
 			return false, err
 		}
 	}
+	genus.Id = base.Id
 	return true, nil
 }
 
@@ -43,7 +47,7 @@ func (s *generaStore) List(opt *models.GenusListOptions) ([]*models.Genus, error
 		opt = &models.GenusListOptions{}
 	}
 	var genera []*models.Genus
-	err := s.dbh.Select(&genera, `SELECT * FROM genera LIMIT $1 OFFSET $2;`, opt.PerPageOrDefault(), opt.Offset())
+	err := s.dbh.Select(&genera, `SELECT g.*, array_agg(s.id) AS species FROM genera g LEFT OUTER JOIN species s ON s.genus_id=g.id GROUP BY g.id LIMIT $1 OFFSET $2;`, opt.PerPageOrDefault(), opt.Offset())
 	if err != nil {
 		return nil, err
 	}
@@ -61,7 +65,8 @@ func (s *generaStore) Update(id int64, genus *models.Genus) (bool, error) {
 	}
 
 	genus.UpdatedAt = time.Now()
-	changed, err := s.dbh.Update(genus)
+
+	changed, err := s.dbh.Update(genus.GenusBase)
 	if err != nil {
 		return false, err
 	}
@@ -79,7 +84,7 @@ func (s *generaStore) Delete(id int64) (bool, error) {
 		return false, err
 	}
 
-	deleted, err := s.dbh.Delete(genus)
+	deleted, err := s.dbh.Delete(genus.GenusBase)
 	if err != nil {
 		return false, err
 	}
diff --git a/datastore/genera_test.go b/datastore/genera_test.go
index b73e998..8f042fc 100644
--- a/datastore/genera_test.go
+++ b/datastore/genera_test.go
@@ -12,15 +12,15 @@ func insertGenus(t *testing.T, tx *modl.Transaction) *models.Genus {
 	// Test on a clean database
 	tx.Exec(`DELETE FROM genera;`)
 
-	genus := newGenus()
-	if err := tx.Insert(genus); err != nil {
+	g := newGenus()
+	if err := tx.Insert(g); err != nil {
 		t.Fatal(err)
 	}
-	return genus
+	return &models.Genus{g, []int64(nil)}
 }
 
-func newGenus() *models.Genus {
-	return &models.Genus{GenusName: "Test Genus"}
+func newGenus() *models.GenusBase {
+	return &models.GenusBase{GenusName: "Test Genus"}
 }
 
 func TestGeneraStore_Get_db(t *testing.T) {
@@ -46,10 +46,11 @@ func TestGeneraStore_Create_db(t *testing.T) {
 	tx, _ := DB.Begin()
 	defer tx.Rollback()
 
-	genus := newGenus()
+	base_genus := newGenus()
+	genus := models.Genus{base_genus, []int64(nil)}
 
 	d := NewDatastore(tx)
-	created, err := d.Genera.Create(genus)
+	created, err := d.Genera.Create(&genus)
 	if err != nil {
 		t.Fatal(err)
 	}
diff --git a/models/genera.go b/models/genera.go
index 0b5bedb..c1094a2 100644
--- a/models/genera.go
+++ b/models/genera.go
@@ -11,7 +11,7 @@ import (
 )
 
 // A Genus is a high-level classifier in bactdb.
-type Genus struct {
+type GenusBase struct {
 	Id        int64     `json:"id,omitempty"`
 	GenusName string    `db:"genus_name" json:"genusName"`
 	CreatedAt time.Time `db:"created_at" json:"createdAt"`
@@ -19,6 +19,11 @@ type Genus struct {
 	DeletedAt NullTime  `db:"deleted_at" json:"deletedAt"`
 }
 
+type Genus struct {
+	*GenusBase
+	Species NullSliceInt64 `db:"species" json:"species"`
+}
+
 type GenusJSON struct {
 	Genus *Genus `json:"genus"`
 }
@@ -31,8 +36,12 @@ func (m *Genus) String() string {
 	return fmt.Sprintf("%v", *m)
 }
 
+func (m *GenusBase) String() string {
+	return fmt.Sprintf("%v", *m)
+}
+
 func NewGenus() *Genus {
-	return &Genus{GenusName: "Test Genus"}
+	return &Genus{&GenusBase{GenusName: "Test Genus"}, make([]int64, 0)}
 }
 
 // GeneraService interacts with the genus-related endpoints in bactdb's API.
diff --git a/models/genera_test.go b/models/genera_test.go
index aa472b8..c749b78 100644
--- a/models/genera_test.go
+++ b/models/genera_test.go
@@ -54,7 +54,7 @@ func TestGeneraService_Create(t *testing.T) {
 	mux.HandleFunc(urlPath(t, router.CreateGenus, nil), func(w http.ResponseWriter, r *http.Request) {
 		called = true
 		testMethod(t, r, "POST")
-		testBody(t, r, `{"genus":{"id":1,"genusName":"Test Genus","createdAt":"0001-01-01T00:00:00Z","updatedAt":"0001-01-01T00:00:00Z","deletedAt":null}}`+"\n")
+		testBody(t, r, `{"genus":{"id":1,"genusName":"Test Genus","createdAt":"0001-01-01T00:00:00Z","updatedAt":"0001-01-01T00:00:00Z","deletedAt":null,"species":[]}}`+"\n")
 
 		w.WriteHeader(http.StatusCreated)
 		writeJSON(w, want)
@@ -124,7 +124,7 @@ func TestGeneraService_Update(t *testing.T) {
 	mux.HandleFunc(urlPath(t, router.UpdateGenus, map[string]string{"Id": "1"}), func(w http.ResponseWriter, r *http.Request) {
 		called = true
 		testMethod(t, r, "PUT")
-		testBody(t, r, `{"genus":{"id":1,"genusName":"Test Genus Updated","createdAt":"0001-01-01T00:00:00Z","updatedAt":"0001-01-01T00:00:00Z","deletedAt":null}}`+"\n")
+		testBody(t, r, `{"genus":{"id":1,"genusName":"Test Genus Updated","createdAt":"0001-01-01T00:00:00Z","updatedAt":"0001-01-01T00:00:00Z","deletedAt":null,"species":[]}}`+"\n")
 
 		w.WriteHeader(http.StatusOK)
 		writeJSON(w, want)
diff --git a/models/species.go b/models/species.go
index 91870a0..f3a40c9 100644
--- a/models/species.go
+++ b/models/species.go
@@ -13,7 +13,7 @@ import (
 // A Species is a high-level classifier in bactdb.
 type Species struct {
 	Id          int64     `json:"id,omitempty"`
-	GenusId     int64     `db:"genus_id" json:"genusId"`
+	GenusId     int64     `db:"genus_id" json:"genus"`
 	SpeciesName string    `db:"species_name" json:"speciesName"`
 	CreatedAt   time.Time `db:"created_at" json:"createdAt"`
 	UpdatedAt   time.Time `db:"updated_at" json:"updatedAt"`
diff --git a/models/species_test.go b/models/species_test.go
index 20f1f8a..bab735b 100644
--- a/models/species_test.go
+++ b/models/species_test.go
@@ -55,7 +55,7 @@ func TestSpeciesService_Create(t *testing.T) {
 	mux.HandleFunc(urlPath(t, router.CreateSpecies, nil), func(w http.ResponseWriter, r *http.Request) {
 		called = true
 		testMethod(t, r, "POST")
-		testBody(t, r, `{"species":{"id":1,"genusId":1,"speciesName":"Test Species","createdAt":"0001-01-01T00:00:00Z","updatedAt":"0001-01-01T00:00:00Z","deletedAt":null}}`+"\n")
+		testBody(t, r, `{"species":{"id":1,"genus":1,"speciesName":"Test Species","createdAt":"0001-01-01T00:00:00Z","updatedAt":"0001-01-01T00:00:00Z","deletedAt":null}}`+"\n")
 
 		w.WriteHeader(http.StatusCreated)
 		writeJSON(w, want)
@@ -124,7 +124,7 @@ func TestSpeciesService_Update(t *testing.T) {
 	mux.HandleFunc(urlPath(t, router.UpdateSpecies, map[string]string{"Id": "1"}), func(w http.ResponseWriter, r *http.Request) {
 		called = true
 		testMethod(t, r, "PUT")
-		testBody(t, r, `{"species":{"id":1,"genusId":1,"speciesName":"Test Species Updated","createdAt":"0001-01-01T00:00:00Z","updatedAt":"0001-01-01T00:00:00Z","deletedAt":null}}`+"\n")
+		testBody(t, r, `{"species":{"id":1,"genus":1,"speciesName":"Test Species Updated","createdAt":"0001-01-01T00:00:00Z","updatedAt":"0001-01-01T00:00:00Z","deletedAt":null}}`+"\n")
 
 		w.WriteHeader(http.StatusOK)
 		writeJSON(w, want)
diff --git a/models/types.go b/models/types.go
index 547c11a..ac356cd 100644
--- a/models/types.go
+++ b/models/types.go
@@ -4,6 +4,9 @@ import (
 	"bytes"
 	"database/sql"
 	"encoding/json"
+	"errors"
+	"strconv"
+	"strings"
 	"time"
 
 	"github.com/lib/pq"
@@ -129,3 +132,27 @@ func (t *NullTime) UnmarshalJSON(b []byte) error {
 	t.Valid = true
 	return err
 }
+
+type NullSliceInt64 []int64
+
+func (i *NullSliceInt64) Scan(src interface{}) error {
+	asBytes, ok := src.([]byte)
+	if !ok {
+		return errors.New("Scan source was not []byte")
+	}
+	asString := string(asBytes)
+	(*i) = strToIntSlice(asString)
+	return nil
+}
+
+func strToIntSlice(s string) []int64 {
+	r := strings.Trim(s, "{}")
+	a := []int64(nil)
+	if r != "NULL" {
+		for _, t := range strings.Split(r, ",") {
+			i, _ := strconv.ParseInt(t, 10, 64)
+			a = append(a, i)
+		}
+	}
+	return a
+}