Chapter 6 Genetics Flashcards
(52 cards)
the inheritance and expression of inherited traits
Genetics
a distinctive association of signs and symptoms occurring together.
Syndrome
physical, biochemical, and physiologic traits of an individual.
Phenotype
hereditary units transmitted from one generation to another.
Genes
Prophase
chromosomes are lining up toward metaphase
Metaphase
chromosomes at the equatorial plane of the cell, long and short arms are joined at the centromere, each identical half is a chromatid
Anaphase
chromatids are in the process of splitting
Telophase
cytokinesis occurs
Mitotic Cycle
G1, S, G2, mitotic division
1st Meiosis
members of each pair of chromosomes line up and exchange segments contacts known as chiasmata. Chromosomes separate, but no splitting of the centromere occurs.NONDISJUNCTION-occasionally both chromosomes that were crossing over do not separate, and both migrate to the same cell.
2nd Meiosis
Essentially a mitotic division (each chromosome splits longitudinally, no replication of DNA occurs before the second meiosis).
Lyon Hypothesis
during the early period of embryonic development,the genetic activity of one of the X chromosomes in each cell of a female embryo is inactivated. The inactivated chromosomes form a contracted structure known as a BARR BODY.
nondisjunction, associated with late maternal age (slanted eyes, shorter stature, heart abnormalities, varied intelligence levels, fissured tongue, gingival and perio disease in 90%, hypodontia, abnormally shaped teeth, anomalies in eruption with malposition and crowding of teeth are common.
Down Syndrome/Trisomy 21
multiple abnormalities in various organs, 70% die within the first 7 months of life=DEADLY, bilateral cleft lip and palate, microphthalmia or anophthalmia.
Trisomy 13
female karyotype, short stature, webbing of neck, edema of hands and feet, low hairline on nape of neck, broad chest with wide spaced nipples, abnormal aorta, sparse body hair, infantile external genitals, primary amenorrhea, and smears have a lack of barr bodies.
most are from nondisjunction of the X chromosome, male phenotype, not detected clinically until puberty (taller than normal, wide hips, female pubic hair distribution, development of female breasts, intelligence levels may be lower than normal, testes are smaller and harder, maxilla is slightly hypoplastic, may be XXXY or XXXXY.
caused by deletion of short arm of chromosome 5, catlike cry at birth, mentally retarded.
Cri du Chat syndrome
deletion of short arm of chromosome 4. Cleft palate and IQ under 30.
Wolf-Hirschhon syndrome
Penetrance
refers to the number of individuals affected
Expressivity
pertains to the degree to which an individual is affected.
autosomal dominant condition, characterized by a cyclic decrease in the number of circulating neutrophils.Systemic manifestations include: fever, malaise, sore throat, and occasionally cutaneous infections.
Cyclic neutropenia
autosomal recessive condition. Oral manifestations include: severe ulcerative gingivitis, gingivostomatitis, ulcerations on tongue and oral mucosa, and repeated episodes lead to severe periodontal disease.
Chronic neutropenia or Kostman syndrome
autosomal recessive inheritance pattern, peripheral blood neutrophils are depressed, and the theory is that chemotaxis is depressed, hyperkeratosis of the palms of hands and soles of feet. At about 1 ½ to 2 years of age, a gingival periodontal inflammatory process develops: edema, bleeding, alveolar bone resorption, and mobility. Both primary and permanent dentition are lost prematurely.
Papillon Lefevre syndrome
autosomal dominant, hyperkeratinization of the palms and soles, and marked hyperkeratinization of labial and lingual gingiva.
Focal palmoplantar and Gingival Hyperkeratosis
a component of several inherited syndromes, composed of very firm tissue with a granular, corrugated surface. Isolated or a component of syndromes:
Gingival fibromatosis
