C10.1: Heredity Flashcards
what is genotype
-your DNA resulting in your genetic makeup
what is phenotype
-what genes are expressed
what is an allele
what are the 2 basic characteristics of an allele?
variant of a gene due to changes in sequencing
- Dominant - affects the phenotype when present in 1 copy
- Recessive- must be present in 2 copies to be expressed
what is a pungent square
-maps of statistical chance of inheriting a condition
how many pairs of chromo for humans
23 pairs, 46 individual (44 autosomes and 2 sex chromo)
what is meiosis
- involved 2 divisions of genetic material and produces 4 haploid cells
- the 4 cells will each have a new assortment of genes and chromo
list the 4 modes of inheritance
- autosomal dominant
- autosomal recessive
- sex linked dominant
- sex linked recessive
describe homogenous and heterogenous in terms of alleles
homo: individual w/ 2 identical alleles for a gene
hetero: individual w/ 2 different alleles for a gene
are recessive or dominant disorders typically more severe
-recessive are more severe and usually produce symptoms at a much earlier age
are dominant disorders w/ early presentation more or less commonly seen?
less commonly because these people tend to be too sick to reproduce
why are dominant disorders w/ late presentation more common?
these individuals can reproduced so the gene is passed on
what is uniparental disomy
-2 copies of an allele from one parent
what are X linked recessive traits
give an example
- always passed from mother from son (son will have the disease)
+ hemophilia A is an example
-daughters are carriers since hemophilia is recessive
when can hemophilia be expressed in girls
-if mom is a carrier and the father had a disease
what is Klinefelters syndrome (XXY)
how does it effect a male?
-affects males who have an extra X chromo passed on from their mother
- will be underdeveloped sexually (no pubic hair or facial hair, may develop breast tissue)
- long arms, legs, large hands and feet
what is Jacobs syndrome (XYY)
how does it effect a male?
-associated w/ violent and aggressive behaviour
what are some common variations of genes
Deletion
Duplication
Translocation - gene has moved to another chromo
Inversion - gene switches positions on the chromo arm
what are some common causes of translocation
exposure to viruses, drugs, radiation
what is the most common cause of T21
maternal nondisjunction
what is nondisjunction
What does it cause?
occurs when the chromo do not separate in meiosis which causes a extra or missing chromo in the gametes
is LMA associated w/ nondisjunction
yes
do individuals who have a translocation always show signs
no
do people w/ translocations have an increase risk of having a child w/ down syndrome
yes
