genetics, epigenetics, & genetic disorders

chromosomes

DNA has 23 pairs (22 pairs autosomes & 1 pair sex) XX - female; XY - male

chromatin

DNA molecules that regulate genetic transcription; includes protein, RNA, DNA

autosomal recessive examples

PKU: disorder from poor diet; deficiency of liver enzyme phenylalanine hydroxylase; can cause mental retardation, microcephaly, delayed speech Tay sachs: unable to break down GM 2 gangliosides of cell membrane where lysosomes are accumulated; destruction of neurons in neurological system; may cause seizures, hearing loss, cherry red spots on eyes more: sickle cell & cystic fibrosis

(TORCH)

Toxoplasmosis Other Rubella Cytomegalovirus Herpes

x linked recessive disorders

X chromosome; more common in males; unaffected mom carries 1 normal 1 mutant allele on x

autosomal dominant

a disorder in which a person needs only one copy of the mutant gene; 50% of inheriting from dominant

genetic info

blueprint that directs the function of cells

autosomal recessive

both are affected and can be unaffected carries

multifactorial inheritance disorders

caused by multiple genes and environmental factors; cleft lip, club foot, heart disease, birth defects

alleles

different forms of a gene at the same locus (ex. blonde and brown hair)

trisomy 21 47, X,Y +21 cri-du-chat. 46, X,Y -5p turners syndrome. 45, X/0 klinefelters 46, X,X,Y

extra chromosome at 21 partial chromo at 5th 0= no monosomy; female short tall male, low secondary sex chara.

single gene disorders

genetic disorders caused by a defective allele at a single gene locus (autosomal dominant/recessive, x linked recessive) results: formation of an abnormal protein

genotype

genetic info stored in the sequence of base pairs; what the genes are (heterozygous or homozygous)

locus

location of a gene on a chromosome

chromosomal disorders

loss of genetic material during meiosis aneuploidy- change in # nondisjuncture- failure for chromosomes to separate monosomy - fatal (45) trisomy - (47); down syndrome

infectious agents

major cause of neonatal morbidity/ mortality - growth retardation - microcephaly

autosomal dominant examples

marfan- connective tissue disorder by changed in skeleton, eyes, and cardiovascular system neurofibromatosis- causes tumors to grow in the nervous sytsem; (1): freckling in armpit or groin; (2) 8th cranial nerve; acoustic - hearing vestibular - balance

histones

proteins that influence how DNA is organized

phenotype

recognizable traits associated with a specific genotype; what you can see (ex. height, eye color)

congenital disorders

teratogenic agents - direct exposure of pregnant women and embryo/fetus - can cause permanent damage to reproductive cells fetal alcohol syndrome - abnormalities due to alc. consumption during pregnancy - baby below 10th percentile folic acid deficiency - spinabifida common

remodeling

tightly packed DNA that changes the chromatin shape which may make change DNA expression