Sets 3 Flashcards
Pedigree
What is pedigree Analysis for ?
its to map out family inheritances, genetic features , matings and an overall family tree as we cant test cross humans
what is the difference between dizygotic and monozygotic ?
dizygotic is when children are born at the same time but they are not identical.
Monozygotic is when children are born at the same time but they are identical
what is different about pedigree ancestors vs and breeding experiments ancestors
all the previous generation for pedigrees are considered ancestors while in breeding exp only parental are considered ancestors
why do human traits not show mendelian inheritance ?
because traits are influenced by more than gene
what are example of single gene traits in humans?
albino, sickle cell & huntington disease
what is albinism ?
an epistatic recessive allele , where your missing and enzyme for melanin production
what is sickle cell disease ?
a recessive mutant allele for hemoglobin gene and provides resistance to malaria
what causes sickle cell ?
a single nucleotide mutation in the HBB gene
what make sickle cell dominance condition dependent
at high altitudes the RBC can turn sickled
is huntington disease domininant or recessive ?
dominant
what is huntington disease ?
a disease that degenerates nerve cells between 30 & 50
what is the percentage it can get passed down to offspring
50%
what does a pedigree for a dominant trait look like ?
appears in each generation
what does a pedigree for a recessive trait look like ?
appears sporadically ( random)
whats an autosomal trait?
shows up on 22/23 pairs has nothing to do with sex
what is a sex linked trait
shows up on 1/23 pairs on either the X or Y chromosome
what are 4 things about autosomal recessive traits
- The affected usually have two unaffected normal parents
- When heterozygotes (has it but is not affected mate they have a 75% chance of normal offspring and 25% change affected
- matings between affected parents produce affected offspring
- Males and females affected are near equal
what are 4 things about autosomal dominant ?
- affected must have at least one affected parent
- mating of normal and heterozygous affected will have a 50/50 of producing normal vs affected
- males and females are affected equally
- appears in majority of generations
what are 3 things about sex-linked recessive ?
- Males are more frequently affected than females bc they only have one copy of a gene
- affected males don’t affect their offspring if female is homozygous
- parents of affected males are usually normal
what are 3 things about sex-linked dominant ?
- Affected individuals usually have one affected parent
- Affected female pass the trait to 50% of their off spring
- affected males will pass it to all female offspring
