Unusual Reproductive Pattern

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Unusual Reproductive Pattern of Mole rats
C.Vamsee Krishna 01st Feb, 2008
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Eusocial behaviour 1. Reproductive division of
labour 2. Caring of young ones 3.
Overlapping generations - Non-chordates
Arthropods - Honey bees - Ants
Hierarchy of the colony
- Queen - Drones - Workers
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Naked mole rats- Heterocephalus glaber
- Savannah - grasslands
- Kenya, Ethiopia and Somalia

• - 8-10 cm long 30-35 g
• - Poor eyesight
• - No fur
• - Sensory whiskers
• No sexual dimorphism
• gt20 years life span
• 65- 300 per colony

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• High O2 affinity
• Sustain drought
• Cold blooded
• No substance P
• Homocoprophage

• - Reproductive
• suppression
• Aggressive, dominant
• queen
• Hormonal
• suppression

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Phenotypic plasticity in female naked mole-rats
after removal from reproductive suppression

• 12-18 month old rats are considered
• 3 animals per cohort (originated from same litter

L4 was used as the representative vertebra as it
provides a reliable index of vertebral
lengthening independent of changes in the size of
intervertebral spaces
J Exp. Biol (2007), 210,4351-58
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ZA Zygomatic arch
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Fig.6. (A) Measurements of total lumbar length
over the course of the 50-week study. Means (
s.e.m.) for each of the 5-week blocks of the
study are plotted on the x-axis. Baseline
corresponds to the 5-week period prior to colony
separation the dotted line indicates the time of
colony separation, and the remaining data blocks
correspond to 1- 45weeks after removal from
reproductive suppression. Significant differences
between the paired females (N2) and males (N2)
or controls (N2) are noted with an asterisk
(Plt0.05). (B) Percent mean gain in total lumbar
spine length over the course of the 50-week
study. Inset numbers on bars indicate the exact
percent gained in lumbar spine from baseline to
45weeks after colony separation for each of the
experimental conditions. Data from cohorts CC1
and CC2 are included.
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Baseline corresponds to the 5-week period prior
to colony separation the dotted line indicates
the time of colony separation, and the remaining
data blocks correspond to 145weeks after
removal from reproductive suppression.
Significant differences between the paired
females and males or controls are noted with an
asterisk.
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Social control of brain morphology

• Low circulating GnRH
• Quiescent hpg axis
• Low LH in males
• Low serum
• testosterone levels

Bed nucleus of strai terminalis (BSTp)
Paraventricular nucleus of hypothalamus
(PVN) Medial nucleus of amygdela (MeA)
Ventromedial nucleus of hypothalamus
(VMH) Suprachaismatic nucleus (SCN)
Anterior cortical amygdaloid nucleus (ACo)
PNAS (2007), 104, 10548-10552
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Studies in context to humans

• Social stress reduce fertility in mammals
• Chronic pain Substance P

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