Unit 2 Flashcards
(23 cards)
What is hermaphroditism?
an organism that contains both functional male and female gametes and can undergo self-fertilization
What is a monoecious organism?
contain both functional male and female gametes in one organism and can undergo self-fertilization but has less genetic variability and relies on mutations.
What does dioecious mean?
one individual only produces one type of gamete and you need two individuals to produce functional gametes and offspring
What kind of pair of chromosomes are X and Y?
heterologous chromosomes
What is the homogametic sex?
the sex that produces all the same gametes with regard to the chromosomes (female in humans)
What is the heterogametic sex?
sex that produces two different gametes with regard to the chromosomes (male in humans)
What is the pseudoautosomal region?
a region on the X and Y chromosomes that is homologous and contains very similar DNA content/sequence to allow X and Y to pair during prophase I
Who discovered X-linked disorders using white eyed fruit flies?
Thomas Hunt Morgan
What is a hemizygous chromosome?
only one allele exists in a diploid individual for that gene
What is true about all P generation parents?
they are all true breeding, so they are homozygous or hemizygous and never heterozygous
What is the ZZ-ZW sex determining system?
ZZ = male and ZW = female
(used in birds, snakes, butterflies, some amphibians, and fishes)
What is the haplodiploidy system?
when the males make sperm through mitosis because they are haploid, but females make eggs through meiosis. Unfertilized eggs become males
What is Turner syndrome?
X or XO chromosomes that leads to females short in stature, sterile, and shortened necks with skin folds
What is non-disjunction?
chromosomes do not separate correctly in either mom or dad during meiosis - gametes are produced with an incorrect chromosome number
What is the result of nondisjunction in meiosis I?
100% abnormal cells
What happens if nondisjunction occurs during meiosis II?
half the cells are abnormal and half are normal
What is Klinefelter syndrome?
XXY genotype in which a male is tall, has long arms and legs and reduced fertility
Define proband
the person from whom the pedigree
What are the three factors that complicate the task of studying the inheritance of human characteristics?
-controlled mating not possible
-long generation time
-small family size
What is concordance?
the percentage of twin pairs that shares a particular trait
What is discordance?
a difference in a trait
How are twin studies used to measure nature vs nurture?
the more influence genes exert over a trait, the higher the differences in concordance between monozygous and dizygous twins
