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Journal of Heredity 2010:101(6):703–709
doi:10.1093/jhered/esq082
Advance Access publication July 19, 2010
Ó The American Genetic Association. 2010. All rights reserved.
For permissions, please email: [email protected].
Genetic Basis of a Color Pattern
Polymorphism in the Coqui Frog
Eleutherodactylus coqui
ERIC M. O’NEILL
AND
KAREN H. BEARD
From the Department of Biology, Utah State University, Logan, UT 84322-5305 (O’Neill); and the Department of Wildland
Resources and the Ecology Center, Utah State University, Logan, UT (Beard). O’Neill is now at the Department of Biology,
University of Kentucky, 101 Thomas Hunt Morgan Building, Lexington, KY 40506-0225.
Address correspondence to Eric M. O’Neill at the address above, or e-mail: [email protected].
Many species of frog exhibit striking color and pattern polymorphisms, but the genetic bases of these traits are not known
for most species. The coqui frog, Eleutherodactylus coqui, a species endemic to the island of Puerto Rico, exhibits a wide variety
of color and pattern polymorphisms including 4 discrete stripe patterns on its dorsal surface and an unstriped morph. We
conducted breeding experiments to determine the mode of inheritance for these 5 dorsal color patterns in E. coqui. We
analyzed results from 14 different cross types, which included 1519 offspring from 71 clutches. We found that color
patterns segregate at ratios consistent with a single autosomal locus, 5-allele model, in which all alleles coding for stripes are
codominant and the allele coding for the unstriped morph is recessive. We propose that this locus be named ‘‘stripes’’ with
alleles B (interocular bar), L (dorsolateral stripes), N (narrow middorsal stripe), W (wide middorsal stripe), and u (unstriped).
The results of this experiment suggest the genetic basis of stripe patterns in this well-studied species and provide a model
for studying the evolution and maintenance of this phenotypic polymorphism.
Key words: Amphibian, codominance, Mendelian inheritance, Puerto Rico
Polymorphism is the occurrence of multiple discontinuous
phenotypes within a single interbreeding population (Mayr
1963). Visible polymorphisms have attracted much attention
from evolutionary biologists because they are easily observed and can be used to study the fundamental processes that
maintain genetic variation (Ford 1975; Gray and McKinnon
2007), especially when their genetic architecture is known.
For example, Gillespie and Tabashnik (1989) and Oxford
and Gillespie (1996) used breeding experiments to determine the mode of inheritance for a color pattern polymorphism in the Hawaiian spider, Theridion grallator. Gillespie
and Oxford (1998) then used this model of inheritance to
demonstrate that the polymorphism is maintained by
balancing selection within populations rather than gene
flow among locally adapted populations. Genetic architecture for most phenotypic polymorphisms is not known, but
it is likely that understanding the inheritance of these traits
will shed light on the roles of different evolutionary
processes in maintaining them.
Frogs exhibit a wide array of color and pattern
polymorphisms including variation in background color
and presence or absence of stripes and spots (Hoffman and
Blouin 2000). The mode of inheritance for these color-based
polymorphisms has been investigated in at least 28 species
(Hoffman and Blouin 2000) but conclusively demonstrated
in only 2, Discoglossus pictus (Lantz 1947) and Rana pipiens
(Volpe 1956, 1961; Anderson and Volpe 1958). Single
generation crosses suggest that in some species background
colors are genetically determined (e.g., Fogleman et al. 1980;
Blouin 1989; Summers et al. 2004), whereas in other species,
there is some element of environmental control (e.g., Wente
and Phillips 2005). Similarly, in some species, color patterns,
such as stripes in Eleutherodactylus (Goin 1950, 1960) and
melanistic patterns in Dendrobates (Summers et al. 2004),
exhibit simple Mendelian inheritance, whereas patterns in
other species, such as spots in R. pipiens, are partly determined by environmental factors (Davidson 1964).
Eleutherodactylus coqui is a diploid (Bogart 1981) frog
endemic to Puerto Rico (Rivero 1978). This species exhibits
considerable variation in background color and both spot
and stripe patterns, and a large number of morphs have
been described (e.g., Schwartz and Henderson 1991; Joglar
1998). Woolbright (2005) simplified this variation into 6
morphs including 4 striped morphs, one spotted morph, and
one morph lacking both stripes and spots. This polymorphism appears to be maintained, at least in part, by
703
Downloaded from jhered.oxfordjournals.org by guest on January 5, 2011
Abstract
Journal of Heredity 2010:101(6)
selection from visual predators and habitat matching
(Woolbright and Stewart 2008). Although these morphs
appear to be highly heritable, the specific genetic architecture is not known. Understanding the genetic architecture
underlying these traits would assist further investigation into
the evolutionary processes affecting this striking polymorphism. Our objective was to determine the mode of
inheritance including the number of loci, number of alleles,
dominance hierarchy, and autosomal versus sex linkage for
stripe patterns found in E. coqui.
Materials and Methods
Frogs were collected from 4 populations in Puerto Rico (El
Yunque Low: lat 18°20#01N, long 65°45#38W; El Yunque
High: lat 18°17#54N, long 65°47#15W; Rio Abajo Low: lat
18°21#28N, long 66°41#02W; Rio Abajo High lat
18°12#59N, long 66°44#51W) in May 2006 and sent to
a laboratory at Utah State University. Controlled breeding
experiments were conducted to determine the mode of
inheritance for stripe patterns and the unstriped morph.
Adults from the same population were established in mixed
pairs and housed in half of a 37.85-l terrarium using
corrugated plastic board as a divider. Prior to the breeding,
704
frogs were scored for stripe patterns and individually marked
using a standard toe-clipping method. Terraria included 1–2
cm of moist sphagnum moss, two 10 cm lengths of PVC
pipe (diameters: 2.54 and 3.81 cm), half of a 0.47-l plastic
cup (cut lengthwise), and a potted plant (Pothos sp.). Relative
humidity inside the terraria was maintained at levels greater
than 95%, temperature at 25 °C, and the photoperiod was
maintained at a constant 12:12 h light:dark. Frogs were fed
vitamin-dusted crickets ad libitum.
Terraria were checked daily for eggs, and each clutch was
removed and placed in a petri dish (95 mm diameter) on
moist paper towel. When clutches were removed, stripe
patterns of adults were confirmed. Petri dishes were watered
and checked for hatching eggs every 2 days. Infertile eggs or
eggs showing evidence of fungal infection were removed
from clutches. Five to seven days after hatching, juvenile
frogs were removed to individual petri dishes (95 mm
diameter) lined with moist paper towel and sphagnum moss
and fed Collembola ad libitum. Color patterns of offspring
were scored at 1 week from the hatching date and confirmed
for each after one month.
The 4 striped and single unstriped color patterns include:
a light colored stripe between the eyes (B 5 interocular bar);
a light hairline stripe extending from the tip of the snout to
Downloaded from jhered.oxfordjournals.org by guest on January 5, 2011
Figure 1. Stripe patterns in Eleutherodactylus coqui showing (A) interoccular bar, (B) dorsolateral stripes, (C) wide middorsal stripe,
(D) narrow middorsal stripe, (E) unstriped, and (F) a combination of dorsolateral stripes and a narrow middorsal stripe.
NA
0.93
NA
0.56
0.54
0.81
0.66
0.77
0.64
0.82
0.97
NA
0.008
NA
0.34
0.37
0.06
1.60
1.11
1.69
0.055
0.001
1:0
1:1.02
0:1
1:1.12
1:1.13
1:1.06
1:0.9:0.7:0.8
1:0.8:0.9:0.7
1:0.6:0.8:0.6
3.2:1
3.02:1
1:0
1:1
0:1
1:1
1:1
1:1
1:1:1:1
1:1:1:1
1:1:1:1
3:1
3:1
u
N.u
N.u
W.u
B.u
L.u
u ,B 5 L
u ,W 5 L
u ,N 5 L
u,L
u,N
Genotypes were assigned to all parents using the proposed model and segregation ratios of offspring.
368
63
0
56
46
36
20
16
9
13
60
12
5
3
3
2
3
2
1
1
2
7
UU
UN
UN
UW
UB
UL
BL
WL
NL
LL
NN
1
2
3
4
5
6
7
8
9
10
11
17
5
8
7
4
3
3
1
1
2
14
—
64
158
—
—
—
—
—
5
—
181
—
—
—
50
—
—
—
12
—
—
—
—
—
—
—
52
—
18
—
—
—
—
—
—
—
—
—
34
13
14
7
42
—
—
—
—
—
—
—
—
—
5
—
—
—
—
—
—
—
—
—
11
—
—
—
—
—
—
—
—
—
16
—
—
—
—
368
127
158
106
98
70
67
53
26
55
241
uu uu
uu Nu
uu NN
uu Wu
uu Bu
uu Lu
Bu Lu
Wu Lu
Nu Lu
Lu Lu
Nu Nu
Expected
ratio
Dominance
hierarchy
Parental
genotypes
Total
BL
WL
NL
L
B
W
N
U
F1 phenotypes
No. of
clutches
No. of
families
Parental
phenotypes
Cross
no.
Table 1
the vent that branches to continue along the leg to the foot
(N 5 narrow middorsal stripe); a wide stripe extending from
the tip of the snout to the vent, not branching and not
continuing to the foot (W 5 wide middorsal stripe); 2 light
stripes extending from the snout or eye to the insertions of
the hind limbs (L 5 dorsolateral stripes); and a solid or
mottled design with no noticeably strong clear stripes (U 5
unstriped; Figure 1). Throughout the text, the same letters
are used to abbreviate phenotypes and their alleles, but
alleles are written in italics. The spotted pattern described by
Woolbright (2005) and Woolbright and Stewart (2008) was
not included in this study because it shows continuous
variation and therefore may be a quantitative trait.
Unstriped frogs were crossed with other unstriped frogs
and with single striped frogs to determine the dominance
hierarchy between the unstriped pattern and each stripe
pattern. Frogs with single stripe patterns were crossed
with frogs with single stripe patterns to further test the
dominance hierarchy and develop a working model of
inheritance of all patterns. Finally, unstriped frogs were
crossed with 2-patterned frogs to test the simplest model of
inheritance against several more complex alternative models
including multiple loci and sex linkage.
The heterogametic sex has not been identified in E. coqui;
therefore, we tested for sex linkage using 2 alternative
models of male and female heterogamy (XY and ZW) that
are common among anurans (Hillis and Green 1990). Only
linkage to the homogametic (X or Z) chromosome was
tested for each of these models because the presence of
each stripe pattern in members of both sexes (O’Neill E,
personal observation) allowed us to reject a model of linkage
to the heterogametic chromosome (Y or W).
To compare the results of our crosses with expected
values under alternative models of inheritance, chi-square tests
for goodness-of-fit were used in SAS 9.1 (SAS Institute, Cary,
NC). When expected values were zero and observed values
were nonzero, no statistical tests were necessary to reject the
null hypothesis. For example, if the model predicted there
should be no offspring with stripes, but we observed offspring
with stripes, the model could not be true. Some crosses were
performed using multiple pairs, in these cases the different
families did not differ in their observed offspring ratios;
therefore, these families were combined for all analyses. All
P values from the chi-squared tests are presented in the tables.
Results
A total of 71 clutches yielded 1519 offspring from 14
different cross types. Stripe patterns scored after 1 week of
hatching did not change after one month. Patterns N and W
were visible at hatching, but B and L were not fully visible
until about 1 week after hatching. Patterns in offspring were
similar to those in adults suggesting that there is little
ontogenetic change in these phenotypes after the first week.
Two percent of the offspring exhibited 2 of the 4 striped
patterns simultaneously but never more than 2 stripe
patterns were observed on a single frog.
705
Downloaded from jhered.oxfordjournals.org by guest on January 5, 2011
Results from crosses testing the dominance hierarchy between the unstriped phenotype (U) and the 4 striped phenotypes (B, L, N, and W)
Observed ratio
v2
P
O’Neill and Beard Genetics of Color Patterns in Coqui Frogs
0.5176
,0.0001
NA
NA
NA
,0.0001
NA
NA
NA
,0.0001
NA
NA
NA
,0.0001
NA
,0.0001
NA
0.419
29.534
NA
NA
NA
29.534
NA
NA
NA
29.534
NA
NA
NA
29.534
NA
29.534
NA
1:1.03
1:1.03:0:0
1:1.03:0:0
1:1.03:0:0
1:1.03:0:0
1:1.03:0:0
1:1.03:0:0
1:1.03:0:0
1:1.03:0:0
1:1.03:0:0
1:1.03:0:0
1:1.03:0:0
1:1.03:0:0
1:1.03:0:0
1:1.03:0:0
1:1.03:0:0
1:1.03:0:0
1:1
1:1:1:1
0:0:0:1
0:1:0:1
1:0:0:1
1:1:1:1
0:0:0:1
1:0:0:1
0:1:0:1
1:1:1:1
0:0:0:1
0:1:0:1
1:0:0:1
1:1:1:1
1:0:0:1
1:1:1:1
0:1:0:1
L is autosomal,
N is X-linked
Female ZW L is autosomal,
N is Z-linked
N is autosomal,
L is Z-linked
Male XY
N is autosomal,
L is X-linked
uu LN
uuuu LuNu
uuuu LLNN
uuuu LuNN
uuuu LLNu
AuAuXuY ANAuXLXu
AuAuXuY ANANXLXL
AuAuXuY ANAuXLXL
AuAuXuY ANANXLXu
AuAuXuY ALAuXNXu
AuAuXuY ALALXNXN
AuAuXuY ALAuXNXN
AuAuXuY ALALXNXu
AuAuZuZu ALAuZNW
AuAuZuZu ALALZNW
AuAuZuZu ANAuZLW
AuAuZuZu ANANZLW
Autosomal
Both autosomal
NA
NA
1
2
86
0
46
40
0
Expected
Observed
phenotypic ratio phenotypic ratio v2
No. of HeteroAutosomal
Putative parental
Total Loci
gametic sex versus sex-linked genotypes M F
LN
U
N
U LN
2
Discussion
12
F1 phenotypes
Cross Parental
No. of
no.
phenotypes M F clutches L
Table 2
706
Crosses 1–9 tested the dominance hierarchy between U
and the 4 stripe patterns: B, L, N, and W (Table 1). Cross 1,
between 2 unstriped parents (U U), resulted in all
unstriped offspring, which suggests that either the allele for
U is recessive and both parents were homozygous or that
the allele for U is dominant and at least one parent was
homozygous. Crosses 2–6, between unstriped (U) and
differently striped frogs (N, W, W, B, and L), resulted in
some offspring, within each clutch, with the parental
patterns at ratios that were not different from 1:1 or 0:1
(Table 1), which supports the hypothesis that the allele for
unstriped is recessive to each allele for stripes and that all
parents in cross 1 were homozygous recessive. Finally, and
critically, crosses 7–11, between 2 striped parents resulted in
some unstriped offspring, which also suggests that the allele
for unstriped is recessive to all alleles for striped patterns.
Crosses 7–9 (B L, W L, and N L, respectively)
resulted in offspring ratios that were not different from
a 1:1:1:1 ratio, and included offspring with no stripes, stripe
patterns from one parent, and stripe patterns from both
parents (Table 1). The simplest explanation for these ratios
is a single-locus model with stripe patterns coded by
codominant alleles and the unstriped pattern coded by
a recessive allele. Alternatively, a 2-locus model with each
parent heterozygous at one locus and homozygous recessive
at the other locus may also explain these results.
Crosses 12–14 (U NL, U BN, and LW U,
respectively) tested the single versus 2-locus model, including autosomal versus sex linkage, for three 2-pattern
combinations (Tables 2–4). All 3 crosses resulted in
offspring ratios that were not different from 1:1 for each
parental stripe pattern (Tables 2–4), which was predicted by
the single-locus model. These ratios were inconsistent with
a 2-locus model, either with both loci autosomal or one
locus as sex linked (Tables 2–4).
Although the above crosses did not directly test for the
allelic relationships between combinations W and B, L, and
B, or N and W because frogs were not available to test these
combinations, the conclusion that these patterns are coded
by different alleles at a single locus can be deduced from the
results of other crosses. For example, cross 12 suggests that
L and N are alleles the same locus, and cross 13 suggests
that N and B are alleles at the same locus; therefore, L and B
should also be alleles at the same locus.
Our crosses suggest that dorsal color pattern variation in E.
coqui is genetically determined and likely the result of a single
autosomal locus with 4 codominant alleles coding for various
stripe patterns and one universally recessive allele coding for
the unstriped pattern. All patterns were found on frogs of both
sexes, further supporting the hypothesis that the locus for
stripe patterns is not linked to a heterogametic chromosome.
We propose that this locus be named ‘‘stripes’’ with alleles B
(interoccular bar), L (dorsolateral stripes), N (narrow middorsal stripe), W (wide middorsal stripe), and u (unstriped).
Downloaded from jhered.oxfordjournals.org by guest on January 5, 2011
Results from crosses testing the number of loci and sex linkage for the phenotypes: U (unstriped), L (dorsolateral stripes), and N (narrow middorsal stripe)
P
Journal of Heredity 2010:101(6)
0.4100
,0.0001
NA
NA
NA
,0.0001
NA
NA
NA
,0.0001
NA
NA
NA
,0.0001
NA
,0.0001
NA
0.67
13.33
NA
NA
NA
13.33
NA
NA
NA
13.33
NA
NA
NA
13.33
NA
13.33
NA
1:0.7
1:0.7:0:0
1:0.7:0:0
1:0.7:0:0
1:0.7:0:0
1:0.7:0:0
1:0.7:0:0
1:0.7:0:0
1:0.7:0:0
1:0.7:0:0
1:0.7:0:0
1:0.7:0:0
1:0.7:0:0
1:0.7:0:0
1:0.7:0:0
1:0.7:0:0
1:0.7:0:0
1:1
1:1:1:1
0:0:0:1
0:1:0:1
1:0:0:1
1:1:1:1
0:0:0:1
1:0:0:1
0:1:0:1
1:1:1:1
0:0:0:1
0:1:0:1
1:0:0:1
1:1:1:1
1:0:0:1
1:1:1:1
0:1:0:1
B is autosomal,
N is X-linked
B is autosomal,
N is Z-linked
N is autosomal,
B is Z-linked
Female
ZW
Male XY
N is autosomal,
B is X-linked
uu BN
uuuu BuNu
uuuu BBNN
uuuu BuNN
uuuu BBNu
AuAuXuY ANAuXBXu
AuAuXuY ANANXBXB
AuAuXuY ANAuXBXB
AuAuXuY ANANXBXu
AuAuXuY ABAuXNXu
AuAuXuY ABABXNXN
AuAuXuY ABAuXNXN
AuAuXuY ABABXNXu
AuAuZuZu ABAuZNW
AuAuZuZu ABABZNW
AuAuZuZu ANAuZBW
AuAuZuZu ANANZBW
Autosomal
Both autosomal
NA
NA
1
2
24
0
0
10
14
1
U BN
13
Expected
Observed
phenotypic ratio phenotypic ratio v2
No. of HeteroAutosomal
Putative parental
Total Loci
gametic sex versus sex-linked genotypes M F
BN
U
N
Cross Parental
No. of
no.
phenotypes M F clutches B
F1 phenotypes
Although some of our crosses had relatively small
sample sizes, we had sufficient power to reject multiple
alternative models that were testable with our data.
Furthermore, sample sizes for tests in this study were
comparable with those in similar studies (e.g., Oxford and
Gillespie 1996; Summers et al. 2004). Further support for
the single autosomal locus model is that no cross produced
any offspring that deviated from the proposed model (e.g.,
an individual with 3 stripe patterns or a striped individual
from a U U cross), and frogs with more than 2 different
stripe patterns have never been found in the field
(O’Neill E, personal observation; Woolbright and Stewart
2008; Peacock et al. 2009). Other alternative models (e.g.,
epistasis) were not testable as null hypotheses because these
did not provide specific expected offspring ratios. Additionally, the possibility of close linkage between multiple loci
remains, but we could not reject the simpler single-locus
model based on the available data.
Dorsal stripe pattern variation is found in at least 80
other species of Eleutherodactylus (Hoffman and Blouin
2000). Of these, the number of loci coding for different
stripe patterns has been investigated in only one other
species, E. nubicola (Goin 1960). Goin (1960) suggested,
from a single clutch collected from a wild-mated female,
that dorsolateral stripe (similar to our L) and middorsal
stripes (similar to our N) were coded by separate loci
in E. nubicola. This suggests that similar stripe patterns
may not be homologous among closely related species
of Eleutherodactylus. Further studies are necessary to
determine to what extent the stripe patterns in this genus
are inherited from a common ancestor representing
homologous parallel evolution (Bull 1975) or the result
of convergent evolution.
The dominance hierarchy found in this study, alleles
coding for dorsal stripes dominant to unstriped, is similar to
that of other amphibians with similar stripe patterns
including frogs of the genera Acris (Pyburn 1961a),
Discoglossus (Lantz 1947), Eleutherodactylus (Goin 1947, 1950,
1960), Rana (Moriwaki 1953; Browder et al. 1966; Ishchenko
and Schupak 1974) and as well as in the salamander,
Plethodon cinereus (Highton 1959). To our knowledge, there
are no studies in which the stripe patterns of amphibians
have been shown to be recessive to unstriped patterns.
Two of the stripe patterns (B and L) exhibited some
ontogenetic change during the first week after hatch but
showed no noticeable change over the next month. Subtle
changes of background and stripe color sometimes occurred
but these did not affect the scoring of phenotypes
(O’Neill E, personal observation). Ontogenetic change in
similar stripe patterns has not been reported in other frogs
(reviewed in Hoffman and Blouin 2000), but changes in
stripe color between juvenile and adult stages do occur in
other frogs (e.g., Pyburn 1961b; Gray 1972). Stripe patterns
are not sexually dimorphic in E. coqui. Most stripe patterns
in other species of frog are not sexually dimorphic
(Hoffman and Blouin 2000), but sexual dimorphism
of dorsolateral stripes occurs in Hyla bokermanni and
H. luteocellata (Rivero 1969).
707
Downloaded from jhered.oxfordjournals.org by guest on January 5, 2011
Table 3 Results from crosses testing the number of loci and sex linkage for the phenotypes: U (unstriped), B (interoccular bar), and N (narrow middorsal stripe)
P
O’Neill and Beard Genetics of Color Patterns in Coqui Frogs
0.3428
,0.0001
NA
NA
NA
,0.0001
NA
,0.0001
NA
,0.0001
NA
NA
NA
,0.0001
NA
NA
NA
0.9
41.8
NA
NA
NA
41.8
NA
41.8
NA
41.8
NA
NA
NA
41.8
NA
NA
NA
1:1.4
1:1.4:0:0
1:1.4:0:0
1:1.4:0:0
1:1.4:0:0
1:1.4:0:0
1:1.4:0:0
1:1.4:0:0
1:1.4:0:0
1:1.4:0:0
1:1.4:0:0
1:1.4:0:0
1:1.4:0:0
1:1.4:0:0
1:1.4:0:0
1:1.4:0:0
1:1.4:0:0
1:1
1:1:1:1
0:0:0:1
0:1:0:1
1:0:0:1
1:1:1:1
1:0:0:1
1:1:1:1
0:1:0:1
1:1:1:1
0:0:0:1
0:1:0:1
1:0:0:1
1:1:1:1
0:0:0:1
1:0:0:1
0:1:0:1
Male XY
W is autosomal,
L is Z-linked
L is autosomal,
W is X-linked
W is autosomal,
L is X-linked
Female ZW L is autosomal,
W is Z-linked
LW uu
LuWu uuuu
LLWW uuuu
LuWW uuuu
LLWu uuuu
ALAuXWY AuAuXuXu
ALALXWY AuAuXuXu
AWAuXLY AuAuXuXu
AWAWXLY AuAuXuXu
ALAuZWZu AuAuZuW
ALALZWZW AuAuZuW
ALAuZWZW AuAuZuW
ALALZWZu AuAuZuW
AWAuZLZu AuAuZuW
AWAWZLZL AuAuZuW
AWAuZLZL AuAuZuW
AWAWZLZu AuAuZuW
Autosomal
Both autosomal
NA
NA
1
2
40
0
17
23
0
Expected
Observed
phenotypic ratio phenotypic ratio v2
No. of HeteroAutosomal
Putative parental
Total loci
gametic sex versus sex-linked genotypes M F
U
LW
Funding
Jack H. Berryman Institute; United States Department of
Agriculture (USDA) Animal and Plant Health Inspection
Service (APHIS) Wildlife Service (WS) Hilo Field Station.
Acknowledgments
W
Permits were provided by the Puerto Rico Departemento de Recourses y
Naturales (Permit number: 06-IC-019) and USU IACUC (no. 1145 and
1251). We thank E. D. Brodie Jr for the use of laboratory space and
supplies, and M. Pfrender and P. Wolf for discussions about inheritance.
We thank L. Giovanetto, J. Poulos, and A. Huff who assisted with animal
collection, G. Jones, M. Cooke, E. Lytle, Y. Kajita, K. Bakkegard, L. Latta,
and K. Latta who assisted with animal husbandry, and 2 anonymous
reviewers for helpful suggestions and comments.
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1
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14
F1 phenotypes
Cross Parental
No. of
no.
phenotypes M F clutches L
Table 4
708
In natural populations of E. coqui, striped frogs are less
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