genetics Flashcards
(30 cards)
present at birth, inherited, genetic or developmental defects due to damage in utero
congenital
consequence of gene changes to the 23 chromosomes in each cell
genetic
abnormal or dislocation of chromosomes
chromosomal
damage to body structures during development or shortly after birth
developmental
combo of genetic predisposition and exposure
multi-factorial
DNA storage unit, threadlike strands of DNA wrapped around protein in each cell nucleus which transmits genetic info
chromosome
code for cells to make protein molecules. 2 copies of each
genes
DNA sequence of a particular gene that occupies a given location on a chromosome. Dominant and recessive.
allele
an individual’s collection of genes, genetic make up or allele combination. Refers to the 2 alleles inherited for a particular gene
genotype
the expression of the genotype contributes to the individual’s observable traits
phenotype
the study of changes in organisms caused by modification of gene expression rather than alteration of the genetic code itself
epigenetics
A male child receives the __ chromosome from his mother and a __ chromosome from his father
- X
- Y
A female child receives a __ chromosome from each parent
X
- occurs when one gene is sufficient to express a trait
- masks the presence of a recessive gene
- can be inherited from a single parent
dominant trait
- expressed only when two copies of the gene are present
- seen only in the absence of the dominant gene
recessive trait
examples of autosomal dominant diseases (3):
- Huntington’s Disease
- Osteogenesis Imperfecta
- Marfan’s Syndrome
autosomal dominant disease:
- 50/50 chance of inheriting from parent
- symptoms start in 30s-40s
- 10-20 yr life span after Dx
- genetic testing available
Huntington’s Disease
autosomal dominant disease:
- brittle bones
- rare congenital disorder of collagen synthesis
- 25% no family history, spontaneous gene mutation
- wide range of presentations; shortened stature, thin skin, joint hypermobility
osteogenesis imperfecta
examples of autosomal recessive genes
- spinal muscular atrophy
- sickle cell anemia
- cystic fibrosis
both parents pass on defective gene to a homozygous (2 recessive genes) child has + genotype and + phenotype.
One parent passes on 1 defective gene to a heterozygous child who is a carrier
autosomal recessive disease occurrence
autosomal recessive disease: progressive atrophy of skeletal muscles and respiratory insufficiency/hypoventilation
spinal muscular atrophy
autosomal recessive disease:
- most common genetic inherited disease in the US
- disease of pancreas - leads to altered production by mucous membranes
- defective gene and protein on chromosome 7
cystic fibrosis
autosomal recessive diseases:
- 1 in 12 African-Americans carry gene for disease
- disease of RBC’s, unable to transport hemoglobin
sickle-cell anemia
- chromosomes either break or fail to separate during gamete formation.
- more common when mother is over age of 35
- not inherited
chromosomal diseases