HUMAN BIOLOGY

iNtroDUCtioN to GeNetiCs 375 wHy does a gamete get only one copy of eacH gene? The two copies of each chromosome in a diploid o ...

376 Chapter 19 Figure 19.5 Animated! A Punnett square shows possible genetic outcomes. A The four possible genotypes of gametes ...

iNtroDUCtioN to GeNetiCs 377 A A a a b b BB A A a a BB b b B A A B b a b b b a A A a a B B A A BB b A bb A b B a a a a B A Initi ...

378 Chapter 19 Rapid destruction of sickle cells leads to anemia Heart failure Kidney failure Abdominal pain Paralysis Heart fai ...

iNtroDUCtioN to GeNetiCs 379 wHy do many genetic traits not Have clear dominant and recessive forms? Pleiotropy is common in hu ...

380 Chapter 19 Figure 19.10 People with polydactyly have extra digits on their hands or feet. Usually the extra digits are dupli ...

iNtroDUCtioN to GeNetiCs 381 wHy are some pHenotypes unpredictable? Observed traits can be difficult to predict when expression ...

382 Chapter 19 expLore on your own summary section 19.1 Genes are specific units of inheritance that are passed to offspring. Ea ...

iNtroDUCtioN to GeNetiCs 383 CritiCaL tHinKinG One gene has alleles A and a. Another has alleles B and b. For each genotype lis ...

384 Chapter 19 Soon after a couple marries, tests show that both the man and the woman are heterozygotes for the recessive alle ...

This chapter expands on previous discussions of homolo- gous chromosomes (19.1). You’ll gain a better understanding of how meios ...

wHat is gene linKage? Linkage refers to the physical distance between genes on a chromosome. Because chromosomes exchange segme ...

Chromosomes and human GenetiCs 387 D Put cells on a microscope slide. Observe. E Photograph one cell through microscope. Enlarge ...

XX XX XY XY XX X X eggs sperm diploid germ cells in female meiosis, gamete formation in both female and male: Fertilization: sex ...

Chromosomes and human GenetiCs 389 How do tHe features and functions of tHe X and y seX cHromosomes compare? The X chromosome, ...

390 Chapter 20 may yield clues to a trait’s genetic basis. For instance, they might figure out that the allele that causes a dis ...

Chromosomes and human GenetiCs 391 wHat can we learn from pedigree analysis? Pedigree analysis may reveal basic inheritance pat ...

392 Chapter 20 amino acid, tyrosine. Excess phenylalanine builds up and may be used by cells to make phenylpyruvic acid. At high ...

Chromosomes and human GenetiCs 393 wHicH genes cause genetic disorders? Recessive and dominant genes on autosomes both may caus ...

394 Chapter 20 inheritance of Genes on the X Chromosome F i g u r e 20.10 Here is one pattern for X-linked inheritance. It shows ...