Genetics 6

Question 1

pedigree analysis

Answer 1

allows geneticist the opportunity to visually examine multiple generations of the same family to look for a pattern of inheritance (X-linked dominant, X-linked recessive, Y-linked, autosomal dominant, autosomal recessive)

Question 2

autosomal dominant pedigree

Answer 2

a person never gets this disorder unless a parent had the disorder (barring spontaneous mutations)

Question 3

autosomal recessive pedigree

Answer 3

parents may be heterozygotes of the disorder and therefor not demonstrate the disorder; if the disorder is not lethal then two afflicted individuals would have an afflicted offspring

Question 4

sex linked (X-chromosome) dominant pedigree

Answer 4

dominant allele is passed from father to daughter, therfore all the daughters and none of the sons of an afflicted father will have the disorder; if the mother is afflicted half of her children (regardless of gender) will be afflicted

Question 5

sex linked (X-chromosome) recessive pedigree

Answer 5

an afflicted father (with normal spouse) passes his x chromosome to his daughters making them carriers, sons will not be afflicted; a carrier mother (with normal spouse) will pass the bad x to half of her sons and half of her daughters, the sons will be afflicted and daughters are carriers; an afflicted mother will have all afflicted sons and all carrier daughters

Question 6

Y-linked pedigrees

Answer 6

passed from father to sona dn expressed in all the males

Question 7

autosomal recessive trait

Answer 7

usually appears in both sexes equally; skips generations; afflicted offspring born to unaffected parents; heterozygous parents have 1/4 children affected; appears more frequently among children of consanguine marriages

Question 8

autosomal dominant trait

Answer 8

usually appears in both sexes equally; both sexes transmit to their offspring; does not skip generations; affect offspring must have an affected parent; one heterozygous parent and one unaffected parent have half offspring affected; unaffected parents do not transmit the trait

Question 9

x-linked recessive trait

Answer 9

usually more males than females affected; affected sons usually born to unaffected mothers; skips generations; half a carrier mother’s sons are affected; never passed father to son; all daughters of affected fathers are carriers

Question 10

X-linked dominant trait

Answer 10

both males and females affected, more often females; does not skip generations; affected fathers will pass the trait to all daughters; affected mothers will pass trait to half of sons and half of daughters

Question 11

Y-linked trait

Answer 11

only males affected; father to son; does not skip generations

Question 12

genetic counseling

Answer 12

talk to individuals about probability of having a special child; but never input their personal opinion on whether to have a child

Question 13

reasons for genetic counseling

Answer 13

known genetic disease in family; given birth to child with defect or genetic disease; child or close relative is intellectually disabled; older woman becomes or tries to be pregnant; husband and wife closely related; difficulties concieving; worry of environmental exposure; prospective parents known carriers

Question 14

prenatal genetic testing

Answer 14

amniocentesis, chorionic villus sampling (CVS)

Question 15

postnatal genetic testing

Answer 15

biochemical tests or genetic screening