autosomal inheritance

contains the cells entire genome

nucleus

half of chromosome

chromatid

Chromosomes are visible with a standard light microscope only during —- of cell division

M phase

is the actual number of chromosomes present in a single-cell nucleus at mitosis

ploidy

chromosome number (1N) is a complete set of one of each chromosome (for humans, 23 individual chromosomes)

haploid

chromosome number (2N) is a complete set of both pairs of all chromosomes

diploid

is the condition of having additional whole sets of extra chromosomes in a nucleus

polyploidy

symbol used in the scientific community to describe haploid cells, meaning a cell or organism has just one complete set of chromosomes

N

The pairs are arranged and numbered by size (largest to smallest) and centromere position:

metacentric to acrocentric

chromosomes have the centromere close to the center of the chromosome, with the p arms and q arms close to the same length

metacentric

chromosomes have a centromere that is not in the center, so the p arms are clearly shorter than the q arms

submetacentric

chromosomes have the centromere at the top of the q arms, and there is little or no p-arm material

acrocentric

This is an organized picture of a complete set of an individuals chromosomes, shows: chromosome count, Structure changes (deletions, duplications, translocations, inversions), and sex chromosomes

karyotype

Dark bands on a karyotype contain less active genes, but are rich in —- and —-

adenine, thymine

Light bands on karyotypes are rich in —- and —- and contain more active genes

guanine, cytosine

a chromosome can be translocated from its position of a “free-standing” separate chromosome and attach to another chromosome, When the chromosome material is present in the correct amount even though its position is different, it is a

balanced translocation

A special type of translocation is one between two acrocentric chromosomes, known as a—-, Situation where someone has 45 instead of 46 chromosomes, The presence of this can be diagnosed by analysis of plain stained karyotypes, If trying to identify specific chromosomes involved, banding will need to be utilized

robertsonian translocation

acrocentric chromosomes (that are affected in robertsonian translocation) are —

13, 14, 15, 21, 22

Situation where someone has 45 instead of 46 chromosomes, Only occurs between the acrocentric chromosomes - two different chromosomes get stuck together and make one big chromosome (most common are 13/14 or 14/21)

robertsonian translocation

if the carrier of robertsonian translocation passes on the stuck together chromosome and a normal copy of the two stuck together the child will ——

be affected

if the robertsonian parent passes on the copy of the stuck together chromosomes only the baby will —-

not be affected

Trisomy —- babies will miscarry and not survive

14

Trisomy — babies may miscarry or survive to birth and have patau syndrome (syndrome is not compatible with life though)

13

Trisomy — is down syndrome

21

When parts of nonhomologous chromosomes are exchanged but the correct amount of genetic material is present, the result is a ——, This can occur with any two chromosome, Genetic material is neither gained nor lost, the person’s development and normal phenotypic appearance are not affected, involves segments of DNA instead of the whole chromosome, Will be considered a translocation carrier only if the translocation is present in all cells

reciprocal translocation

becomes a problem when the translocated and normal chromosomes are the ones passed down instead of just the translocated chromosomes or normal chromosomes - depending on severity could miscarry or have learning disabilities or birth defects

reciprocal translocation

Whenever a translocation is —-, the person’s phenotype and function are not affected by the translocation

balanced

BOTH are Balanced translocations where you yourself may not be affected, but your offspring might

reciprocal, robertsonian

Results when a child inherits more than or less than two copies of a chromosome or part of a chromosome from a parent, Results in abnormal anatomic development and physiologic functions, Trisomy, Monosomy, and other chromosomal disorders

unbalanced translocation

Involves having an extra copy of one chromosome, Can result from nondisjunction during gametogenesis, Can also result from gamete formation in a person who is a balanced translocation carrier

trisomy

is a cell division error where chromosomes fail to separate properly so we can have to many or too few chromosomes, is more common with advancing maternal age

nondisjunction

trisomy —, —, and —- are the most common

13, 18, 21

occurs from trisomy 13, Affects females more often than males, Most are stillborn; live-born infants usually die within the first year (90%), Many features; not every person has them all, Individuals share variations in skin, hair, and eye color with family members

patau syndrome

Decreased intellectual development to severely compromised, Small head (microcephaly), Cleft lip (with or without cleft palate), Clenched fist with overlapping fingers, Single palmar crease, Extra digits on hands or feet (polydactyly), all lower jaw (micrognathia), Low-set ears, Rocker-bottom feet, Fusion of digits on hands or feet (syndactyly), Small, close-set eyes (could be fused), Many heart malformations, Abnormal rotation of internal organs, Deafness and visual problems, Seizures, Apnea

patau syndrome

occurs from trisomy 18, Affects females more often than males, Most are stillborn; live-born infants usually die within the first year, rocker bottom feet, overlapping fingers, clenched fists

edwards syndrome

Decreased intellectual development to severely compromised, Small, strawberry-shaped head with receding chin and elongated occiput, Clenched fist with overlapping fingers, Single palmar creases; arch-patterned fingerprints, Low-set, abnormal ears, Rocker-bottom feet with a prominent heel, Kidney malformations, Heart malformations (atrial-septal defects, ventricular-septal defects, coarctation of the aorta), Esophageal atresia, Omphalocele, Inguinal and umbilical hernias, Brain cysts

edwards syndrome

occurs from trisomy 21, Most common trisomy among live-born infants, Affects males and females and all races equally

Down syndrome

Decreased intellectual development (potential is not predictable), Congenital heart defects (especially cardiac cushion defects), Palmar crease across palms, Flat faces, Widely spaced eyes, Slightly low-set ears, Small, short nose, Brushfield spots (speckling) on iris, Short neck with limited motion and extra skin folds, Short little finger that curves inward, Wide gap between first and second toes, Intestinal obstruction (at birth), Shorter stature than siblings, Thicker lips, with slightly protruding tongue, Poor muscle tone and reflexes (at birth), More likely to have vision and hearing losses at earlier ages, Cataract formation, Hypothyroidism, Premature aging, Increased risk for leukemia

Down syndrome

males with Down syndrome are usually —- but females with down syndrome are not usually

infertile

Rare in gene-coding regions, more common than duplications, Larger scales of this are more likely to result in observable phenotypes, Random events from chromosome breakage and rearrangements during gametogenesis

partial chromosome deletions

examples of identified partial deletions:

WAGR syndrome, retinoblastoma, cri du chat

Wilms Tumor, aniridia, genitourinary malformations, and intellectual disability, comes from the partial deletion of chromosome 11, GU malformations can range from first degree hypospadias (urethral opening is on the side of the penis), or as severe as complete extrophy of the bladder, 40% of children with these symptoms go on to develop wilms tumor before the age of 5

WAGR syndrome

comes from partial deletion of chromosome 13, Rare malignant tumor of the retina occurring in early childhood, Inherited condition genetically, but no family history present, Autosomal-dominant pattern, Greatest risk in individuals missing the RB gene on chromosome 13

retinoblastoma

comes from partial deletion of chromosome 5, Infants will have a distinctive cat like cry, Cleft lip, microcephaly, cleft palate, wide spaced eyes, epicanthal folds, low set ears, small chin, various heart defects, reduced cognition, The larger the deletion the greater the degree of reduced cognition

cri du chat

Deletion of maternal chromosome 15 from q11 to q13, Only paternal expression of alleles in this chromosome region, Normal features at birth - Phenotype more obvious as infant ages, Developmental delay and microcephaly, Progressively reduced cognition, Unsteady, clumsy gait with jerky motions, Inappropriate smiling and laughing, Excitable personality, Poor speech development, Hand-waving or hand-flapping motions, Seizure disorder, Hair, skin, and eye color lighter than that of siblings, Also known as happy puppet syndrome

angelman syndrome

Deletion of paternal chromosome 15 from q11 to q13, Only maternal expression of alleles in this chromosome region, normal features at birth - Most notable problems in infancy include hypotonia, poor suckling reflex, and failure to thrive but then Most outstanding feature is an insatiable appetite that manifests by the age of 3

prader willi syndrome

A rare occurrence in which the genomic input of one parent’s allele or alleles fails to contribute to the offspring’s phenotype, This is known to occur occasionally through the process of uniparental disomy, in which both chromosomes of a pair are contributed by only one parent

genomic imprinting

A condition in which two (or more) different karyotypes are consistently present in one individual (from different cells) - a person only has trisomy 21 in some cells so will have some Down syndrome traits but not all because not all of the cells are affected, As cells grow and divide they may be able to push out the abnormalities

mosaicism

the most common chromosomal abnormality among live born infants is —

trisomy 21

monosomy of autosomal chromosomes appears to be —-

lethal

involves an extra copy of every chromosome, and trisomy involves an extra copy of only one chromosome

triploidy

Which clinical feature is a common finding for infants with trisomy 21, trisomy 18, and trisomy 13?

single palmar crease

edwards syndrome is —-

trisomy 18

WAGR syndrome comes from problems with chromosome —

11

retinoblastoma comes from problems with chromosome —

13

cri du chat comes from problems with chromosome —

5

angelman and prader willi syndrome come from problems with chromosome —

15