L17- genotype, phenotype and inheritance Flashcards
(53 cards)
central dogma

genotype
our set of genes
phenotype
our traits- proteins
what factors influence our phenotype
- e.g. Genetic disorders like CF (genetic mechanism)
- infection (environment)
- non commiunicable disease (genotype and environment)

what is a gene
A sequence of DNA found at a specific location within chromosomes, which codes for a protein.
an allele is a
form of a gene
how many genes do we have
25,000
- all indiviudals have two copies of each given gene ( one maternala nd one paternal)
many alleles of a gene
within a population e.g. why we have different hair and eye colours
- gene codes of hair colour
- allele codes for the specific colour
homozygous
tow alleles of a gene are the same
heterozygous
two alleles of a gene are different
hemizygous
only one allele of a gene on the X chromosome (male only)
dominant
a dominant alleles in a heterozygote determines phenotype (Aa – would have A phenotype)
recessive
the non-dominant allele in a heterozygote is called recessive.
co- dominance
where both alleles have equal contribution to phenotype e.g. ABO blood types
co-dominance and ABO blood groups
Human isoglutamin gene codes for glycoproteins on the surface of RBC.
Three alleles for blood type:
- A or I^A
- B or I^B
- O or I^O
We have 2 alleles each
- Allele A is dominant over O
- Allele B is dominant over allele O
- Neither A or B is dominant over the other= Co-dominant

in a pedigree each line represents
a separate generation
oldest sibling on the pedigree will be
furthest to the left
how to draw a pedigree- reminder of symbols

describe III.17

youngest of 8 children, married with no children
in autosomal recessive disorders, heteozygotes will be
unaffected
in autososmal recessive disorders males and females
equally affects
in autososmal recessive disorders, if both parents are heterozygotes
Two heterozygotes have 25% chance of having affected offspring












