Sex Determination Flashcards
What is the symbol for male and female in a pedigree chart?
Male = square
Female=circle
How do you show a carrier in pedigree analysis?
Half shaded half white
What are the 3 primary patterns of inheritance?
Autosomal recessive
Autosomal dominance
Sex-linked
What does autosomal recessive mean?
Autosomal: Gene is on one of the autosomes (Chromosomes 1-22). Male and female offspring equally likely to inherit trait.
If neither parents has the trait then it is recessive // can skip a generation
Name 3 examples of autosomal recessive diseases
Attached ear lobes
Tay-Sachs disease
Sickle-cell anaemia
Albinism
What does autosomal dominant mean?
Male and female offspring likely as gene on autosome.
Dominant means it is always expressed if present
What type of inheritance is Huntington’s disease?
What is the disease
Autosomal Dominant.
Quick degeneration of brain cells after 30
What type of inheritance is polydactyly?
Autosomal dominance
Describe what X-linked means
Trait usually seen in males- hemizygous, as trait passed from mother. Cannot be passed to sons but always passed to daughters
Name 2 examples of X-linked diseases
Haemophilia
Colour-blindness
Asexual reproduction is also known as what?
Parthenogenic reproduction
Define Hermaphrodite / bisexual / monoecious
(individuals with both male/female reproductive organs)
Define Ghonochoric / unisexual / dioecious
(male/female reproductive organs in separate individuals)
Describe an example of location-dependent sex determination
Larvae
Bottom = female
Top = male
How does temperature-dependent sex determination work?
Temperature sensitive aromatase: converts androgens (male hormone e.g. testosterone) to oestrogens (female hormones e.g. estradiol)
