MEEMF 2011 – ED4 No arquivo ed4.nex está o alinhamento dos

MEEMF 2011 – ED4
No arquivo ed4.nex está o alinhamento dos genes codificadores de proteínas
mitocondriais de alguns mamíferos. Considere os seguintes informações de
calibração retirados de Benton e Donoghue, (2007, Mol. Biol. Evol.).
Dating the Tree of Life 27
Table 1
Constraints on Calibration Dates for Branching Points in the Tree of Life
Minimum
Age Constraint
Node
Human–chimp
Human–macaque
Mouse–rat
Rabbit–mouse
Human–mouse
Dog–cat
Dog–horse
Cow–sheep
Cow–pig
Cow–dog
Human–cow
Human–armadillo
Tenrec–elephant
Human–tenrec
Opossum–kangaroo
Human–opossum
Human–platypus
Chicken–zebrafinch
Emu–chicken
Bird–crocodile
Crocodile–lizard
Mammal–bird
Human–toad
Equivalent to Clade
Age-Indicative
Fossil
Homini–Pan
Hominoidea–Cercopithecoidea
Mus lineage–Rattus lineage
Glires
Archonta–Glires (Euarchontoglires)
Caniformia–Feliformia
Carnivora–Perissodactyla
Bovinae–Antilopinae
Ruminantia/Tylopoda–Suiformes
Ferungulata
Euarchontoglires–Laurasiatheria
Boreoeutheria–Xenarthra
Afrosoricida/Tubulidentata–Paenungulata
Boreoeutheria/Xenarthra–Afrotheria
Ameridelphia–Australidelphia
Eutheria–Metatheria
Theriimorpha–Australosphenida
Galloanserae–Neoaves (Neognathae)
Palaeognathae–Neognathae (Neornithes)
Avemetatarsalia/Ornithodira–Crurotarsi
Archosauromorpha–Lepidosauromorpha
Sauropsida–Synapsida (Amniota)
Reptiliomorpha–Batrachomorpha
Sahelanthropus
Proconsul
Progonomys
Heomys
Heomys
Tapocyon
Tetraclaenodon
Eotragus
Mixtotherium
Zhelestidae
Zhelestidae
Zhelestidae
Phosphatherium
Zhelestidae
Pucadelphys
Eomaia
Phascolotherium
Vegavis
Vegavis
Vjushkovisaurus
Protorosaurus
Hylonomus
Lethiscus
Maximum
Age Constraint
Youngest
Recommended
Oldest
Recommended
Date (MYA) Date (MYA) date (MYA) Date (MYA)
6.5
23.5 6 0.5
11.0
61.7 6 0.2
61.7 6 0.2
43 6 0.2
62.5 6 0.2
18.3
48.5 6 0.2
96.2 6 0.9
96.2 6 0.9
96.2 6 0.9
48.6 6 0.2
96.2 6 0.9
61.7 6 0.2
124.6 6 0.01
166.5 6 4.0
66
66
237 6 2.0
260.4 6 0.7
313.4 6 1.1
332.4 6 2.0
6.5
23.0
11.0
61.5
61.5
42.8
62.3
18.3
48.3
95.3
95.3
95.3
48.4
95.3
61.5
124.6
162.5
66
66
235
259.7
312.3
330.4
10
33.8 6 0.1
12.3
99.6 6 0.9
99.6 6 0.9
63.6 6 0.2
70.6 6 0.6
28.4 6 0.1
53.5
112 6 1
112 6 1
112 6 1
112 6 1
112 6 1
70.6 6 0.6
136.4 6 2.0
189.6 6 1.5
85.8 6 0.7
85.8 6 0.7
249.7 6 0.7
299 6 0.8
328.8 6 1.6
348 6 2.1
10
33.9
12.3
100.5
100.5
63.8
71.2
28.5
53.5
113
113
113
113
113
71.2
138.4
191.1
86.5
86.5
250.4
299.8
330.4
350.1
Evidence
Biostratigraphy
Biostratigraphy
Magnetostratigraphy
Biostratigraphy
Biostratigraphy
Bio/Magnetostraigraphy
Bio/Magnetostratigraphy
Biostratigraphy
Biostratigraphy
Biostratigraphy
Biostratigraphy
Biostratigraphy
Biostratigraphy
Biostratigraphy
Biostratigraphy
Direct date
Biostratigraphy
Biostratigraphy
Biostratigraphy
Biostratigraphy
Biostratigraphy
Biostratigraphy
Biostratigraphy
NOTE.—Branching points are indicated for key species, and their larger clade equivalences. The oldest and youngest dates are given, based on the literature, and on the
Cambridge 2004 timescale (Gradstein et al. 2004). The youngest date is given for the minimum age constraint, and the oldest for the maximum age constraint, based on the date
of the geological formation containing the age indicative fossil. The recommended dates are the youngest possible (i.e., minimum) date for the minimum constraint, and the
oldest possible (i.e., maximum) for the maximum constraint.
are poorly calibrated. Furthermore, molecular clock analy- ical evidence of one or more apomorphies of the clade in
Usando
o BEAST, estime o tempo de divergência entre:
ses are rarely, if ever, framed around the availability of question. In all cases, the date is sought for branching bereliable calibration dates. Rather, they are characterized tween 2 extant species, and so we pursued each of the 2
by a)
scientifically
interesting questions and the availability lineages back to the point at which they shared their last
Monodon/Lagenorhynchus
of appropriate sequence data (Hedges and Kumar 2004). common ancestor, based on current phylogenetic evidence.
b) Pontoporia/(Monodon, Lagenorhynchus)
Together, these facts require that well-researched cali- Having 2 lineages meant, we could select the older of the 2
bration
are available(Pontoporia,
for the majority of
available oldest
fossils (table 1).
c) dates
Platanista/
(Monodon,
Lagenorhynchus))
sequence data and, to this end, we provide detailed assessThe second step is to date the geological formation in
d) Megaptera/ (Platanista, (Pontoporia, (Monodon, Lagenorhynchus)))
ments of the paleontological data constraining the timing of which the oldest fossil, or fossils, occurs, or occur. The
lineage splits between the main genomic models.
identity of that geological formation is clear in all cases—earliestseu
members
of theirmão
Zebrafish (ostariophysean) and
Use como calibração a separação Homothecom
grupo
Pufferfish (euteleost) lineages, for example, both date from
Minimum Constraints on Divergence Dates e a idade
(Euarchontoglires/Lausiatheria)
da
raiz
(Eutheria/Metatheria).
the lithographic limestones of the Obere Solnhofener
The indicated range of minimum branching dates Schichten of southern Germany. A geological formation
(table 1) reflects both uncertainty in the dates (stratigraphic is a well-constrained succession of rocks with a clearly
error) as well as the inferred duration of the fossiliferous marked base and top. In most cases, there is an extensive
unit. Such a small range of dates, less than 1% in many biostratigraphic literature devoted to establishing the relacases, may seem startlingly low, but current geological tive age of the unit in question. For the Solnhofen lithotimescales (Gradstein et al. 2004) offer that level of preci- graphic limestones, ammonites and other fossils place
sion. The quoted age range does not incorporate an estimate the unit in the lower Tithonian stage (zeta 2a zone) of the
of uncertainty about whether the oldest fossil really belongs Upper Jurassic. That is a relative age, refined to a zonal level
to the clade or about whether the clade might have origi- that may be less than 1 Myr in duration. Absolute chrononated much earlier. The date arose from a 2-step process: stratigraphic ages are then assigned by reference to the inter1) Which is the oldest relevant fossil within the clade in national standard, with precise ages established by
question? 2) What is the best current age estimate for radiometric methods. The zeta 2a zone is part of the Hybothe geological formation that includes that fossil?
niticeras hybonotum ammonite zone, the base of which coThe first step relied on our reading of current paleon- incides with the base of the normal-polarity Chron M22An
tological data, and wide consultation on each date with rel- magnetozone that is dated at 150.8 MYA 6 0.1 Myr (Ogg
evant experts. We excluded all uncertain or scrappy fossils, 2005); a minimum constraint on its age can be derived from the
and retained only those for which there is definitive anatom- base of the succeeding, Semiformiceras darwini ammonite