Lecture 24 sensory trade offs
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Lecture 24 : Sensory trade offs. 11/30/09. Opportunities at Shady Grove Adventist Hospital. Student scribes to work in emergency room If interested, contact Michele Liscum Scribes America [email protected] Final projects next week. NO assignment due this week

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Lecture 24 : Sensory trade offs

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Lecture 24 sensory trade offs

Lecture 24 : Sensory trade offs

11/30/09


Opportunities at shady grove adventist hospital

Opportunities at Shady Grove Adventist Hospital

  • Student scribes to work in emergency room

  • If interested, contact

    • Michele Liscum

    • Scribes America

    • [email protected]


Final projects next week

Final projects next week

  • NO assignment due this week

  • Next week presentations

    • Monday and Wednesday

  • Send me your powerpoint by noon on the day of your talk

  • Final projects due on Wednesday


Monday

Monday


Wenesday

Wenesday


Questions

Questions

  • What are the trade off between senses?

  • When are senses lost? Is this related to gain in other senses?


Vision

Vision

  • Can have independent gain and loss of spectral sensitivities

    • Lose if no longer need

    • Gain if new need arises


Lecture 24 sensory trade offs 1375265

LWS

Lamprey LWS

RH2

Lamprey RHB

RH1

Lamprey RHA

SWS2

Lamprey S2

SWS1

Lamprey S1


Lecture 24 sensory trade offs 1375265

Trezise and Collin 2005


Lecture 24 sensory trade offs 1375265

RH2

SWS1

Monotreme

SWS2

Davies et al 2007 Platypus

SWS2


Marine mammals

Marine mammals

  • Evolved from land mammals

  • Land mammals have two cone opsins

    • SWS1

    • M/LWS


Placental mammals

Placental mammals

X = loss SWS1

X

X

X


Marine mammals1

Marine mammals

Unique gene losses in each lineage - separate events


New world vs old world

New world vs Old world


Multiple lws opsin genes in ow and nw monkeys

Multiple LWS opsin genes in OW and NW monkeys

OW

NW


Human red and green opsins

A

F

A

530 nm

560 nm

S

Y

T

F261Y=+10 nm

A269T=+14 nm

A164S=+2 nm

Human red and green opsins


Lws opsin sequences in primates

LWS opsin sequences in primates

+2+10+14

164261269

Human560 S Y T

Human530 A F A

Capuchin563 S Y T

Capuchin550 A F T

Capuchin535 A F A

Marmoset563 S Y T

Marmoset556 AY T

Marmoset543 AYA

Combos of same sites in MWS and LWS of all OW monkeys


Lws opsin sequences

LWS opsin sequences

+2+10+14

164261269

Human560 S Y T

Human530 A F A

Capuchin563 S Y T

Capuchin550 A F T

Capuchin535 A F A

Marmoset563 S Y T

Marmoset556 AY T

Marmoset543 AYA

Alleles

Allele = different form of a gene which can vary in a group / population


Lecture 24 sensory trade offs 1375265

Duplication event which caused tandem array of red and green genes to form

OW

NW

Duplicated about 30 MYa


Lecture 24 sensory trade offs 1375265

Tandem array in OW

Human

Gorilla

Chimpanzee

Marmoset

Capuchin

Howler

OW

NW monkeys - alleles

NW


Most nw monkeys

Most NW monkeys

LWS SWS1

Males XY

3 possible dichromats

Females XX

3 possible dichromats (R/R, O/O or G/G) and

3 possible trichromats (R/O, R/G or O/G)


Allele tree

Allele tree

Old world gene duplication occurred 30 Mya

5-8% divergent

Howler monkey duplication is more recent

2.7% different


Why need trichromacy

Why need trichromacy

  • Following slides from talk by Jim Bowmaker, University College London


Lecture 24 sensory trade offs 1375265

Why trichromacy? Why two ‘LWS’ cone types? Dichromacy with a single LWS and an SWS1 cone type gives no red-green discrimination.


Lecture 24 sensory trade offs 1375265

Trichromacy with two ‘LWS’ cone types and an SWS1 cone gives red-green discrimination.

Ripe fruit and young, more reddish leaves can be detected against the dappled green foliage.


Lecture 24 sensory trade offs 1375265

Gelada, Ethiopia Theropithecus gelada

Vervet monkey, East Africa Cercopithecus aethiops

Trichromacy enables new color signaling in primates.


Zhang and webb 2003

Zhang and Webb 2003


Vomeronasal receptor pathway

Vomeronasal receptor pathway

G protein

V1R, V2R

Phospholipase C

Trp2

Humans, great apes and OW monkeys do not have functioning VNO. Why?


Trp2 is knocked out in ow primates

Trp2 is knocked out in OW primates

+ = open reading frame s = stop codon


Many v1r genes are also pseudogenes

Many V1R genes are also pseudogenes


Vomeronasal receptor pathway1

Vomeronasal receptor pathway

G protein

V1R, V2R

Phospholipase C

Trp2

Humans, great apes and OW monkeys do not have functioning VNO. Why?


Coincidence in time

Coincidence in time

  • Trp2 gene lost 23-35 Mya

  • Lost V1R gene about 24 MY

  • Opsin gene duplication was <35 MY

  • Primates use sexual skin swelling to indicate ovulatory status

    • If can use vision to determine ovulatory status then don’t need pheromones to communicate


Webb et al 2004

Webb et al 2004


Relationship between vision and vno

Relationship between vision and VNO?

Human Trichromat No VNO

OW primates Trichromat No VNO

NW primates Dichromat VNO

Howler Trichromat ??

Mammals Dichromat VNO

Birds Tetrachromat No VNO


If vision displaces vno

If vision displaces VNO

  • Expect howler to also have lost VNO pathway

    • However, they find TRP2 gene is intact in howlers

  • Howlers also show behavioral evidence that use VNO

    • Scent marking


Webb s explanation

Webb’s explanation


Gilad et al 2004 does it happen in olfaction

Gilad et al 2004: Does it happen in olfaction?


Method

Method

  • Used degenerate primers to amplify suite of OR genes

    • Examine 18 primate species

    • Sequence 100 genes

    • Calc % pseudo

  • Test method on human and mouse OR genes to see if identify diverse set


Test in human and mouse

Test in human and mouse

Human

Mouse

Actual #

This method


Or pseudogenes

% OR pseudogenes


Results comparison

Results comparison


Or pseudogenes1

% OR pseudogenes


Gains and losses

Gains and losses

  • Do seem to be some trade offs

  • Will any of you find evidence for this in the species you are examining?


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