Evolutionary Development Biology – Lecture 5 – Partner Choising
Partner choice lead to sexual selection:
1. Increase attractiveness to the other sex
2. Increase competitiveness to the same sex
Partner choising on chemical signals
Pheromones (steroids) (volatile chemical compound): chemical compounds that
influence sexual behaviour of potential partners. They act as aphrodisiac (stimulates
sexual desire)
Pheromones
Pheromones are detected via olfactory receptor in
antennas they bind and send electrical signal to CNS.
In female this lead to aphrodisiac in male anti-aphrodisiac
may cause aggression.
Different effect on male and female? Neural pathway is
identical but there is differentiation between the two sexes as a result of which
signals reach different neurons in males and females.
Pheromones (androstenone) in vertebrates/mammals
335 olfactory receptors are screened for androstenone activation.
Receptor OD7R4 is strongly activated by androstone – pheromones
(androstenone) are detected via OD7R4 in vomeronsal organ.,
Two alleles:
OD7D4-RT: chemical, sweaty, cat urine (unpleasant) (sensitive)
OD7D4-WM: sweet, vanilla, fresh (pleasant) (insensitive)
Androstenone is related to hormone testosterone.
Androstenone is present in sweat and urine
Androstenone is important in large mammals.
Androsterone does not seen to influence parter choice. No significant differences
measure in emotional sexual arousal.
Pleasantness of
The smell
Females show preference for partners with immune genes (MHC II
(major histocompatibility complex)) different then there own –
increase change of their children being hetrozygous – heterozygote
male odours
are more resistant against infection diseases because have more
variation in antigen – the more antigen variants the better unknown
pathogen can be attacked.
Chromosome 6: genetic linkage between MHC complex and olfactory
recepotors
Outcome of the experiment is influenced by the menstruation cycle and the use of
contraceptives
During menstruation females are les attractive and less pleasant
Women who swallow the pill found men with similar MHC much more
attractive watch out: first generation anti-conceptive seemed to influence
Partner choice lead to sexual selection:
1. Increase attractiveness to the other sex
2. Increase competitiveness to the same sex
Partner choising on chemical signals
Pheromones (steroids) (volatile chemical compound): chemical compounds that
influence sexual behaviour of potential partners. They act as aphrodisiac (stimulates
sexual desire)
Pheromones
Pheromones are detected via olfactory receptor in
antennas they bind and send electrical signal to CNS.
In female this lead to aphrodisiac in male anti-aphrodisiac
may cause aggression.
Different effect on male and female? Neural pathway is
identical but there is differentiation between the two sexes as a result of which
signals reach different neurons in males and females.
Pheromones (androstenone) in vertebrates/mammals
335 olfactory receptors are screened for androstenone activation.
Receptor OD7R4 is strongly activated by androstone – pheromones
(androstenone) are detected via OD7R4 in vomeronsal organ.,
Two alleles:
OD7D4-RT: chemical, sweaty, cat urine (unpleasant) (sensitive)
OD7D4-WM: sweet, vanilla, fresh (pleasant) (insensitive)
Androstenone is related to hormone testosterone.
Androstenone is present in sweat and urine
Androstenone is important in large mammals.
Androsterone does not seen to influence parter choice. No significant differences
measure in emotional sexual arousal.
Pleasantness of
The smell
Females show preference for partners with immune genes (MHC II
(major histocompatibility complex)) different then there own –
increase change of their children being hetrozygous – heterozygote
male odours
are more resistant against infection diseases because have more
variation in antigen – the more antigen variants the better unknown
pathogen can be attacked.
Chromosome 6: genetic linkage between MHC complex and olfactory
recepotors
Outcome of the experiment is influenced by the menstruation cycle and the use of
contraceptives
During menstruation females are les attractive and less pleasant
Women who swallow the pill found men with similar MHC much more
attractive watch out: first generation anti-conceptive seemed to influence
