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BIO Chapter 15
Chromosomal Basis of Inheritance
Term | Definition |
---|---|
Who is Thomas Hunt Morgan? | geneticist that experimented with the color of fruit fly eyes |
Why did Morgan study fruit flies? | easy to control, produce a lot of offspring |
What major discover about genetics did Morgan make? | sex-linked genetic traits |
How many pairs of autosomes in a human? | 22 |
How many sex chromosomes? | 1 pair |
Sex linked recessive disorders- | disorders what are linked to the X chromosome and occur in men much more frequently than in women |
Mary Lyon’s dosage compensation hypothesis- | Barr bodies |
Barr bodies- | an inactivated chromosome to deal with an “extra” one |
Nondisjunction- | results in alterations in chromosome number, when chromosomes fail to split correctly in mitosis or meiosis |
Aneuploidy- | a change in chromosome number that effects on or several chromosomes in a cell |
Polyploidy- | change in chromosome number that effects a whole set of chromosomes |
Trisomy- | extra chromosome in women that results in a major increase in miscarriage likelihood |
Monosomy- | missing a chromosome |
Trisomy 21- | down syndrome |
Trisomy 18- | Edwards syndrome |
Trisomy 13- | Patau syndrome |
47 XXX- | healthy female with two barr bodies |
45 X- | infertile female, turner syndrome |
47 XYY- | taller than average male, healthy, no conception issues |
47 XXY0 | Klinefelter syndrome in males, conception issues |
4 types of alterations in chromosome structure- | deletions, duplications, translocation, inversion |
Deletion- | removes a chromosomal segment, sever symptoms |
Duplications- | repeat a segment of a chromosome, symptoms can include speech and language delays, social anxiety, diagnosis of autism spectrum disorder, seizures |
Inversion- | reverses a segment within a chromosome, no huge effects normally |
Translocation- | moves a segment from one chromosomes to a non-homologous chromosome |
Genomic imprinting- | gene expression occurs from only one allele |
Mechanism of genomic imprinting- | epigenetic process that can involve DNA methylation to turn off the expression of an allele |