The young female faeders' complete lack of production of chicks in the captive flock is unusual.
But many make up for this lack of choice by having affairs: 40% of Cousin's warbler chicks are not fathered by their mother's mate.
The same lack of waterproofing leads chicks to die from heat stroke on hot days, when a dip in the ocean is the best way to cool down but requires a waterproof coat.
The lack of a full-length chick Ednrb cDNA at the time of this study precluded direct pharmacological studies aimed at selecting a specific EDNRB antagonist.
The lack of peripheral astigmatism in chicks was not due to differences in corneal shape.
The lack of peripheral astigmatism in chicks also excludes a role in emmetropization.
A similar cis-inhibition of Dll4 signalling by Jag1 has been described in stalk cells during retina angiogenesis [43] and might explain the lack of Dll1 activity in the chick gain-of-function experiments [34].
It was demonstrated by Haddad et al. [ 17, 18] that the exoribonuclease PNPase (polynucleotide phosphorylase) is involved in low-temperature survival of C. jejuni, and that the lack of PNPase induces swimming limitation, chick colonization delay and decrease of cell adhesion/invasion ability.
Finally, unlike the wild-type mouse limb bud, the Shh−/− mutant posterior limb bud mesoderm does not cause digit duplications when grafted to the anterior border of chick limb buds, and therefore lacks polarizing activity.
Species, age or ecological differences (e.g. flight may encourage encoding of global axes for pigeons and lack of flight, local cues for chicks), may guide how surface geometry is encoded, and these are all empirical issues deserving further examination.
This fact probably explains the difference in turnover rates between the chick and roach fish diets and the lack of convergence for the exponential model for the chick diet, whose initial isotopic difference was less marked (Table 1A; Fig. 2A).
